Air quality measurements in the Netherlands 2021

RIVM Annual report
Version 1

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Authors

Affiliation

Pleuni Bongers

National Institute for Public Health and the Environment (RIVM)

Dennis Mooibroek

Published

July 28, 2025

1 Air quality monitoring network in the Netherlands

Air quality in the Netherlands is monitored by the National Air Quality Monitoring Network (LML), which is administered by the National Institute for Public Health and the Environment (RIVM) in collaboration with its regional partners. The resulting data provide a detailed picture of air quality and the concentrations of the various pollutants at the monitoring stations.

This annual report gives an overview of the key measurement values for specific pollutants in 2021 from measurements by RIVM and two of its regional partners DCMR Environmental Protection Agency (DCMR) and The Public Health Service of Amsterdam (GGD Amsterdam). Measurements are carried out under EN ISO/IEC 17025:2017 accreditation by RIVM under L224 in collaboration with its regional partners DCMR (L520) and GGD Amsterdam (L426) who are accredited according to the same ISO standard. Analysis of heavy metals is outsourced to an external analytical laboratory that is accredited according to EN ISO/IEC 17025:2017 under L026. See Appendix A for an overview of all the accreditation certificate numbers for the measurements in this report. Appendix A also includes an overview of ambient air quality limit values. Besides the current limit values from the 2008/50/EC and 2004/107/EC directives, this report will take into account the revised EU directive (2024/2881) on ambient air quality and cleaner air for Europe and, in some occasions, the Air Quality Guideline (AQG) levels from the World Health Organisation (WHO) reported in 2021.

The air quality monitoring sites have specific encoding for EU reporting, where all sites in the Netherlands start with NL, followed by 10 for RIVM sites (L224), 01 for DCMR measurement sites (L520) and 49 for sites from GGD Amsterdam (L426). The remaining 3 numbers denote the unique monitoring site. For information on the used monitoring instruments and sampling practices, see the metadata on the LML data catalog on the public RIVM website. For additional information including measurement uncertainties, please consult the accompanying README.

2 Key concentration values per component

The upcoming tables contain the key statistics per component for 2021, where mean is the yearly averaged concentration - based on either hourly or daily (24-h) values, P50 and P98 denote the 50th and 98th percentile, max is the maximum measured concentration value, n is the number of valid data points in hours or days, % is the percentage of valid data, max.roll.24 denotes the maximum value of the rolling 24-h mean and max.roll.8 of the 8-h mean. All of these values are in µg/m³ unless otherwise specified and with the exception of values for lead, arsenic, cadmium, nickel and benzo(a)pyrene, which are in ng/m³. Columns that are colored in red indicate an exceedance of the EU limit values from 2008/50/EC or 2004/107/EC, orange represents an exceedance of the revised EU limit values from EU Directive 2024/2881. For several pollutants, additional columns have been added relating to component-specific target values. The summary tables where the annual means have been grouped by site type, only contain yearly averages where data capture meets EU requirements.

2.1 Nitrogen dioxide

	mean¹	P50	P98	max	median	n	%	exc_200²	max.roll.24	max.roll.8
Key statistics for NO₂ in 2021
Rural Background
NL01497	20.8	15.9	58.5	76.3	15.9	496	5.7	0	51.1	59.8
NL10107	12.6	10.6	35.1	60.1	10.6	8733	99.7	0	42.5	52.0
NL10131	12.7	10.3	37.0	67.6	10.3	8722	99.6	0	42.7	46.7
NL10133	10.1	7.9	29.4	51.9	7.9	8623	98.4	0	36.6	40.2
NL10230	14.8	10.6	50.3	355.1	10.6	8694	99.2	12	92.8	211.1
NL10235	13.8	11.1	40.6	98.1	11.1	8736	99.7	0	44.0	55.9
NL10246	13.9	11.1	43.3	86.9	11.1	8747	99.9	0	46.8	64.8
NL10301	11.7	8.9	41.7	82.6	8.9	8660	98.9	0	52.5	63.0
NL10318	12.6	9.4	42.3	106.6	9.4	8693	99.2	0	56.7	92.9
NL10437	14.7	11.6	45.6	104.5	11.6	8680	99.1	0	57.5	81.2
NL10444	11.4	8.4	40.4	73.7	8.4	8640	98.6	0	44.5	52.0
NL10538	10.6	6.2	42.5	195.3	6.2	8571	97.8	0	45.6	81.9
NL10617	9.5	7.3	34.1	54.1	7.3	8643	98.7	0	41.5	45.8
NL10633	11.5	8.9	35.5	66.6	8.9	8680	99.1	0	45.5	49.8
NL10644	13.0	10.3	38.3	65.6	10.3	8641	98.6	0	41.9	51.3
NL10722	10.6	8.6	33.1	59.1	8.6	8715	99.5	0	40.5	46.9
NL10738	10.9	8.7	33.9	59.2	8.7	8694	99.2	0	40.6	45.1
NL10807	8.4	6.5	28.8	44.5	6.5	8728	99.6	0	38.0	42.3
NL10818	8.2	6.2	28.5	49.1	6.2	8576	97.9	0	35.3	40.6
NL10918	7.1	4.8	28.4	68.3	4.8	8629	98.5	0	43.1	47.7
NL10929	7.4	5.8	24.6	48.1	5.8	8516	97.2	0	32.0	36.0
NL10934	6.0	4.6	22.3	65.1	4.6	8720	99.5	0	32.5	36.0
NL49703	14.9	10.8	48.3	95.5	10.8	8453	96.5	0	51.8	66.3
Urban Background
NL01485	21.7	18.3	61.3	133.7	18.3	8506	97.1	0	79.4	117.3
NL01488	21.1	16.6	65.3	130.9	16.6	8577	97.9	0	87.3	114.0
NL01494	24.7	20.6	67.2	127.8	20.6	8709	99.4	0	86.3	114.8
NL01495	24.8	21.2	68.4	150.3	21.2	8739	99.8	0	112.7	143.9
NL01912	21.8	17.7	62.2	110.9	17.7	8627	98.5	0	71.3	99.2
NL10138	12.3	9.8	37.7	67.8	9.8	8469	96.7	0	46.6	49.2
NL10241	17.3	13.6	51.2	103.7	13.6	8648	98.7	0	54.2	70.5
NL10247	13.4	10.5	40.4	64.4	10.5	8693	99.2	0	52.3	57.8
NL10404	19.7	14.5	65.3	151.4	14.5	8667	98.9	0	83.5	101.4
NL10418	23.3	19.3	62.6	119.3	19.3	8740	99.8	0	85.2	113.2
NL10442	17.3	13.8	51.7	98.5	13.8	8559	97.7	0	47.7	64.3
NL10446	20.8	16.4	61.3	119.4	16.4	8716	99.5	0	78.2	103.2
NL10643	15.8	12.4	47.2	88.6	12.4	8553	97.6	0	49.1	62.2
NL10742	18.0	15.0	49.8	78.6	15.0	8726	99.6	0	56.7	68.6
NL10938	8.2	6.0	29.5	79.1	6.0	8554	97.6	0	37.9	47.5
NL49003	16.1	12.7	49.0	115.8	12.7	8715	99.5	0	63.2	82.8
NL49014	17.4	14.1	48.9	79.5	14.1	8670	99.0	0	48.8	54.8
NL49019	20.3	16.5	57.0	138.9	16.5	8662	98.9	0	68.1	100.9
NL49021	14.7	11.7	44.3	97.8	11.7	8717	99.5	0	51.7	68.8
NL49022	16.3	12.1	51.5	85.1	12.1	8691	99.2	0	58.1	63.4
NL49701	16.6	11.9	54.0	94.3	11.9	8737	99.7	0	55.5	74.8
Roadside
NL01487	30.7	27.1	76.6	137.9	27.1	8730	99.7	0	103.8	120.0
NL01489	26.0	22.9	68.6	117.7	22.9	8733	99.7	0	73.3	91.2
NL01491	27.6	24.1	68.2	129.5	24.1	8405	95.9	0	91.6	110.1
NL01493	31.6	28.1	75.6	140.0	28.1	8709	99.4	0	96.8	117.5
NL10136	19.0	16.4	51.6	101.0	16.4	8463	96.6	0	51.2	69.1
NL10236	17.8	14.7	48.0	79.0	14.7	8694	99.2	0	50.9	61.9
NL10237	21.6	18.6	55.0	96.0	18.6	8735	99.7	0	56.0	74.0
NL10240	22.6	19.4	59.4	101.0	19.4	8595	98.1	0	60.0	72.0
NL10445	23.8	20.4	66.0	137.8	20.4	8700	99.3	0	84.6	104.4
NL10449	27.4	23.8	69.0	134.9	23.8	8737	99.7	0	91.3	113.9
NL10550	18.8	15.7	51.3	111.3	15.7	8546	97.6	0	68.5	71.1
NL10636	19.2	16.1	53.1	103.3	16.1	8713	99.5	0	59.5	70.8
NL10639	20.9	17.3	57.7	99.4	17.3	8713	99.5	0	60.7	82.8
NL10641	20.5	18.2	51.1	84.8	18.2	8653	98.8	0	52.9	61.3
NL10741	25.5	23.0	59.6	116.3	23.0	8691	99.2	0	65.1	75.7
NL10937	18.1	16.0	46.5	99.9	16.0	8732	99.7	0	66.7	74.1
NL49002	32.4	29.3	76.5	158.1	29.3	8734	99.7	0	101.7	119.0
NL49007	34.0	31.1	79.3	127.9	31.1	8622	98.4	0	100.0	98.9
NL49012	25.9	21.9	68.5	153.2	21.9	8737	99.7	0	91.1	122.0
NL49017	24.4	21.0	62.2	104.1	21.0	8639	98.6	0	69.2	82.3
NL49020	28.3	24.9	69.6	115.0	24.9	8612	98.3	0	74.0	86.3
Industrial
NL01496	23.9	20.4	76.6	161.2	20.4	8723	99.6	0	111.7	142.2
NL01913	17.9	14.7	52.9	110.2	14.7	8635	98.6	0	65.2	91.5
NL49704	20.6	15.5	62.5	132.6	15.5	8573	97.9	0	76.5	95.8
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the future EU limit value from 01-01-2030 (2024/2881/EC) and red of the current EU limit value (2008/50/EC)
² Number of hours where concentrations exceed 200 µg/m³ - Color indicates exceedance of > 3 times (orange) or > 18 times (red) per calendar year

Table 1: Key concentration values for nitrogen dioxide in 2021 (in μg/m³)

type	mean	n
Annual NO₂ means per station type in 2021
Rural Background	11.20	22
Urban Background	18.18	21
Roadside	24.58	21
Industrial	20.81	3

Table 2: Summary table for nitrogen dioxide in 2021 (in μg/m³)

2.2 Particulate matter

	mean¹	P50	P98	max	median	n	%	max.roll.24	max.roll.8	exc_50_d²
Key statistics for PM₁₀ in 2021
Rural Background
NL01497	16.8	15.8	34.7	55.7	15.8	743	8.5	32.9	36.2	0
NL10131	17.4	14.7	54.4	301.4	14.7	8707	99.4	92.5	136.1	4
NL10133	14.9	13.4	45.4	104.3	13.4	8694	99.2	64.4	73.7	2
NL10230	16.6	14.7	51.8	392.3	14.7	8670	99.0	141.4	97.7	2
NL10235	15.4	14.7	41.5	206.7	14.7	8727	99.6	82.5	80.4	1
NL10246	15.3	13.4	46.7	110.7	13.4	8738	99.7	61.5	82.2	1
NL10318	15.9	14.7	48.0	261.7	14.7	8615	98.3	56.6	80.8	1
NL10437	15.4	13.4	49.2	160.6	13.4	8632	98.5	65.0	83.3	1
NL10444	14.9	13.4	40.3	352.6	13.4	8644	98.7	261.3	264.6	1
NL10538	13.0	12.1	37.7	106.8	12.1	8534	97.4	62.8	72.1	0
NL10617	14.4	12.1	48.0	396.1	12.1	8613	98.3	108.3	112.9	1
NL10633	13.8	12.1	44.1	264.3	12.1	8650	98.7	181.1	181.1	1
NL10644	14.4	13.4	44.1	289.9	13.4	8600	98.2	130.6	126.9	0
NL10722	14.6	13.4	42.8	164.4	13.4	8731	99.7	71.2	79.8	1
NL10738	17.4	15.9	50.5	400.0	15.9	8721	99.6	400.0	244.9	4
NL10807	15.0	13.4	45.4	186.2	13.4	8631	98.5	126.9	128.8	1
NL10818	14.7	13.4	44.1	264.3	13.4	8639	98.6	88.6	104.3	1
NL10918	13.0	10.8	42.8	167.0	10.8	8630	98.5	64.5	85.9	0
NL10929	12.3	10.8	39.0	265.6	10.8	8328	95.1	67.4	80.6	0
NL10934	14.2	12.1	42.8	192.6	12.1	8610	98.3	76.5	80.1	0
NL49703	14.7	12.5	38.6	304.7	12.5	8466	96.6	232.2	242.4	1
Urban Background
NL01485	18.5	16.7	44.5	331.5	16.7	8660	98.9	331.5	121.0	2
NL01488	19.4	17.5	47.5	390.1	17.5	8563	97.8	390.1	193.1	3
NL01494	20.0	17.9	49.1	392.9	17.9	8630	98.5	327.3	176.6	2
NL01495	17.8	15.6	45.0	390.5	15.6	8604	98.2	85.0	183.8	1
NL01912	19.4	17.2	48.0	437.1	17.2	8741	99.8	310.8	160.7	2
NL10138	14.4	13.4	41.5	239.9	13.4	8717	99.5	239.9	89.6	2
NL10241	16.4	14.7	48.0	237.4	14.7	8626	98.5	215.0	159.5	2
NL10247	16.7	14.7	53.1	204.1	14.7	8714	99.5	94.0	81.9	2
NL10404	18.1	15.9	46.7	1457.2	15.9	8659	98.8	1359.3	705.0	1
NL10418	19.1	17.2	51.8	183.6	17.2	8720	99.5	174.7	106.0	2
NL10442	15.9	14.7	42.8	428.1	14.7	8744	99.8	337.9	167.2	2
NL10446	16.2	14.7	45.4	635.5	14.7	8697	99.3	530.5	348.3	1
NL49014	15.5	13.3	40.7	262.0	13.3	8588	98.0	164.5	165.9	1
NL49016	17.3	15.4	44.4	253.6	15.4	8344	95.3	201.9	206.8	1
NL49701	16.1	13.9	39.8	209.4	13.9	8689	99.2	174.7	181.6	1
Roadside
NL01487	20.2	17.5	55.7	512.1	17.5	8557	97.7	512.1	223.2	8
NL01489	19.6	17.3	48.2	326.8	17.3	8702	99.3	241.2	167.6	4
NL01491	18.3	16.5	44.9	321.2	16.5	8623	98.4	300.5	197.9	1
NL01493	19.9	17.9	49.1	220.4	17.9	8708	99.4	207.8	131.3	3
NL10136	17.0	14.7	49.2	224.6	14.7	8579	97.9	224.6	91.0	2
NL10236	17.1	15.9	49.2	302.7	15.9	8667	98.9	302.7	156.1	3
NL10237	18.8	17.2	51.8	197.7	17.2	8679	99.1	197.7	113.4	2
NL10240	18.0	17.2	50.5	356.4	17.2	8423	96.2	306.5	231.8	2
NL10445	19.0	17.2	49.2	1555.8	17.2	8686	99.2	1265.2	723.1	1
NL10449	19.8	17.2	51.8	1063.0	17.2	8717	99.5	894.7	399.3	4
NL10550	18.0	15.9	49.2	446.0	15.9	8619	98.4	303.6	296.1	2
NL10636	16.0	14.7	42.8	446.0	14.7	8679	99.1	446.0	263.2	1
NL10639	16.6	15.9	48.0	273.2	15.9	8680	99.1	265.6	219.5	3
NL10641	14.8	13.4	44.1	324.4	13.4	8729	99.6	147.4	147.4	1
NL10741	19.4	18.5	55.6	232.3	18.5	8658	98.8	215.6	182.3	7
NL10937	17.7	15.9	48.0	385.9	15.9	8726	99.6	385.9	116.9	0
NL49007	17.7	15.6	45.9	349.0	15.6	8653	98.8	283.9	242.5	2
NL49012	18.7	16.8	44.7	405.8	16.8	8700	99.3	382.6	246.9	3
NL49017	17.9	16.2	44.9	317.3	16.2	8525	97.3	317.3	188.0	1
NL49020	18.9	16.6	48.8	450.9	16.6	8626	98.5	333.8	236.3	1
Industrial
NL01496	19.4	17.5	46.0	481.5	17.5	8674	99.0	86.0	184.3	1
NL01913	22.0	18.3	65.2	238.5	18.3	8652	98.8	238.5	97.7	9
NL49557	21.0	18.4	59.2	193.3	18.4	8427	96.2	71.4	112.3	7
NL49704	15.6	12.8	41.9	269.1	12.8	8664	98.9	205.0	220.1	2
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the future EU limit value from 01-01-2030 (2024/2881/EC) and red of the current EU limit value (2008/50/EC)
² Number of days where concentrations exceed 50 µg/m³ - Red color indicates exceedance of > 35 times per calendar year

Table 3: Key concentration values for PM₁₀ in 2021 (in μg/m³)

type	mean	n
Annual PM₁₀ means per station type in 2021
Rural Background	14.88	20
Urban Background	17.38	15
Roadside	18.17	20
Industrial	19.50	4

Table 4: Summary table for PM₁₀ in 2021 (in μg/m³)

	mean¹	P50	P98	max	median	n	%	max.roll.24	max.roll.8
Key statistics for PM_2.5 in 2021
Rural Background
NL10131	10.6	8.7	31.8	81.5	8.7	8625	98.5	69.2	69.6
NL10230	9.6	7.4	33.1	99.4	7.4	8556	97.7	99.4	70.3
NL10444	8.5	6.9	28.1	253.2	6.9	8544	97.5	192.1	195.0
NL10538	7.3	5.6	28.0	74.1	5.6	8433	96.3	51.7	59.5
NL10644	8.1	6.2	29.3	114.0	6.2	8364	95.5	94.0	86.9
NL10738	9.8	7.6	32.4	322.1	7.6	8645	98.7	322.1	198.3
NL10934	6.5	4.7	24.8	73.6	4.7	8640	98.6	55.4	56.5
NL49703	8.7	7.0	29.0	288.6	7.0	8429	96.2	215.2	224.2
Urban Background
NL01485	10.3	8.2	31.2	175.2	8.2	8750	99.9	175.2	54.9
NL01488	10.8	8.8	33.1	314.0	8.8	8544	97.5	314.0	162.1
NL01494	11.6	9.5	34.0	346.6	9.5	8690	99.2	290.9	156.2
NL01495	10.8	8.8	33.5	421.5	8.8	8540	97.5	61.7	91.2
NL01912	11.8	9.6	35.8	99.1	9.6	8288	94.6	57.7	67.6
NL10138	7.8	6.1	27.0	143.7	6.1	8561	97.7	143.7	56.0
NL10241	7.7	5.6	29.9	159.6	5.6	8175	93.3	152.7	109.3
NL10247	11.3	9.5	33.4	73.0	9.5	8647	98.7	73.0	61.3
NL10404	6.7	4.8	28.4	317.3	4.8	8319	95.0	317.3	74.6
NL10418	8.5	6.6	29.2	125.1	6.6	8655	98.8	116.1	71.4
NL10643	10.8	8.9	31.4	274.4	8.9	8637	98.6	248.3	157.8
NL10742	10.8	8.9	32.6	181.3	8.9	8619	98.4	181.3	135.0
NL10821	7.9	5.9	28.1	191.2	5.9	8527	97.3	191.2	103.6
NL10938	7.7	6.0	27.4	206.9	6.0	8690	99.2	206.9	76.9
NL49014	9.8	7.9	31.5	241.3	7.9	8588	98.0	155.9	156.8
NL49016	9.8	8.0	31.9	230.5	8.0	8658	98.8	185.8	191.0
NL49701	10.1	8.3	30.5	207.0	8.3	8479	96.8	168.1	174.5
Roadside
NL01487	11.8	9.7	35.2	541.4	9.7	8262	94.3	541.4	224.3
NL01489	10.1	8.0	31.9	297.8	8.0	8688	99.2	211.4	145.3
NL01491	10.2	8.2	30.9	287.8	8.2	8631	98.5	272.7	181.2
NL10136	8.8	6.8	30.2	132.6	6.8	8393	95.8	132.6	57.2
NL10240	11.1	9.0	33.5	279.5	9.0	8473	96.7	243.8	179.9
NL10448	9.6	7.8	30.3	187.4	7.8	8706	99.4	182.2	109.2
NL10449	9.6	7.6	30.5	727.5	7.6	8689	99.2	727.5	185.3
NL10636	10.8	8.8	32.6	316.5	8.8	8689	99.2	316.5	188.1
NL10641	8.8	6.9	30.1	145.6	6.9	8662	98.9	113.6	113.6
NL10741	10.0	7.9	31.2	156.7	7.9	8624	98.4	145.2	124.0
NL10937	7.2	5.5	25.4	242.5	5.5	8627	98.5	242.5	76.5
NL49007	10.2	8.3	32.4	289.5	8.3	8656	98.8	231.4	205.1
NL49012	10.9	8.8	33.4	382.1	8.8	8707	99.4	364.4	232.8
NL49017	11.4	9.5	32.9	319.9	9.5	8689	99.2	319.9	180.6
Industrial
NL01496	9.6	7.5	32.1	96.5	7.5	8627	98.5	40.9	48.8
NL01913	12.5	9.8	38.1	207.2	9.8	8652	98.8	207.2	67.1
NL49557	11.2	8.2	40.1	95.0	8.2	8591	98.1	48.4	58.6
NL49704	10.2	8.2	31.1	257.0	8.2	8679	99.1	185.9	200.0
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the future EU limit value from 01-01-2030 (2024/2881/EC) and red of the current EU limit value (2008/50/EC)

Table 5: Key concentration values for PM_2.5 in 2021 (in μg/m³)

type	mean	n
Annual PM_2.5 means per station type in 2021
Rural Background	8.66	8
Urban Background	9.67	17
Roadside	10.04	14
Industrial	10.89	4

Table 6: Summary table for PM_2.5 in 2021 (in μg/m³)

	2019	2020	2021	average_3y
Statistics to determine the AEI for PM_2.5
Urban Background
NL01494	12.8	9.7	11.6	11.4
NL10138	8.5	7.2	7.7	7.8
NL10241	9.1	7.6	7.7	8.1
NL10247	11.9	9.9	11.3	11.0
NL10404	8.6	7.1	6.7	7.5
NL10418	9.5	8.4	8.4	8.8
NL10643	10.5	9.0	10.9	10.1
NL10742	10.6	9.8	10.8	10.4
NL10821	8.9	7.6	7.8	8.1
NL10938	8.5	6.9	7.7	7.7
NL49014	10.4	9.6	9.8	9.9
NL49701	11.2	9.9	10.2	10.4
* A hyphen is used in case of insufficient valid data to provide an annual mean

Table 7: Annual means for PM_2.5 (in μg/m³) on selected urban background sites and the 3-year average to determine the Average Exposure Indicator (AEI)

The Average Exposure Indicator (AEI) for PM_2.5 assesses the general population’s long-term exposure to fine particles in urban areas and is based on a 3-year average measured at urban background stations. The AEI in year 2021 is 9.3 µg/m³.

2.3 Sulphur dioxide

	mean¹	P50	P98	max	median	n	%	exc_350_h²	max.roll.24	max.roll.8	exc_125_d³	mean_winter⁴
Key statistics for SO₂ in 2021
Rural Background
NL10133	0.4	0.2	3.0	11.7	0.2	8489	96.9	0	3.4	5.7	0	0.3
NL10318	0.7	0.4	4.3	23.0	0.4	8686	99.2	0	5.3	11.0	0	0.6
NL10444	0.6	0.3	3.6	15.1	0.3	8557	97.7	0	4.8	7.4	0	0.6
NL10644	0.5	0.3	2.5	24.9	0.3	8599	98.2	0	2.7	5.2	0	0.5
NL10722	0.4	0.2	3.6	21.0	0.2	8678	99.1	0	8.1	11.1	0	0.5
NL10934	0.2	0.1	1.2	8.8	0.1	8668	99.0	0	2.1	3.8	0	0.2
Urban Background
NL01485	1.9	1.0	12.2	78.1	1.0	8718	99.5	0	16.7	23.7	0	1.8
NL01495	0.8	0.5	5.4	98.3	0.5	8738	99.7	0	11.4	29.5	0	0.8
NL49016	1.3	1.2	3.7	21.8	1.2	8704	99.4	0	5.0	10.8	0	1.1
Industrial
NL01484	4.6	2.1	26.2	344.6	2.1	8339	95.2	0	107.2	194.1	0	5.2
NL01496	1.0	0.6	5.6	44.3	0.6	8721	99.6	0	18.0	29.9	0	1.2
NL49704	1.0	0.7	4.2	32.0	0.7	8628	98.5	0	6.3	14.3	0	1.0
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the yearly limit value of 20 µg/m³ (2024/2881/EC)
² Number of hours where concentrations exceed 350 µg/m³ - Color indicates exceedance of > 3 times (orange) or > 24 times (red) per calendar year
³ Number of days where concentrations exceed 125 µg/m³ - Red color indicates exceedance of > 3 times per calendar year
⁴ Mean concentrations in winter (1 October 2021 to 31 March 2022) for assessing the critical level for the protection of vegetation and natural ecosystems - Red color indicates exceedance of 20 µg/m³

Table 8: Key concentration values for sulphur dioxide in 2021 (in μg/m³)

type	mean	n
Annual SO₂ means per station type in 2021
Rural Background	0.48	6
Urban Background	1.36	3
Industrial	2.19	3

Table 9: Summary table for sulphur dioxide in 2021 (in μg/m³)

2.4 Ozone

For ozone, there is no limit value based on the annual mean, instead the number of days where the maximum daily rolling 8-h mean of ozone concentrations exceed 120 µg/m³ is assessed. For the long-term objective, this may not be exceeded on any day. The target value for the protection of human health takes into account data that is averaged over three years. Until 1 January 2030, 120 µg/m³ may not be exceeded on more than 25 days per calendar year averaged over three years and thereafter, it’s set to a maximum of 18 days. See Table 12 for the number of exceedance days in 2019, 2020 and 2021 and their 3-year averages.

The ‘Accumulated Ozone exposure over a Threshold of 40 parts per billion’ (AOT40), expressed in (µg/m³) × hours, means the sum of the difference between hourly concentrations greater than 80 µg/m³ (= 40 parts per billion) and 80 µg/m³ over a given period using only the 1-hour values measured between 8:00 and 20:00 Central European Time (CET) each day (EU Directive 2024/2881). The target value for AOT40 is 18000 µg/m³ x h averaged over 5 years. Note that the aot40 values in the table are only for the year 2021 and based on measurements from May up to and including July.

Another widely used ozone indicator for health impact assessment recommended by WHO called somo35 is given in the table. This represents the sum of all daily maximum 8 hour moving averages over 35 ppb - equivalent to 70 µg/m³.

	mean	P50	P98	max	median	n	%	max.roll.24	max.roll.8	exc_120¹	aot40²	somo35³
Key statistics for O₃ in 2021
Rural Background
NL10107	46.6	46.2	106.6	151.4	46.2	8639	98.6	107.3	143.5	10	9258.4	2906.4
NL10131	45.3	45.3	100.0	200.7	45.3	8632	98.5	104.1	151.0	9	7611.6	2334.9
NL10230	46.7	47.1	102.6	163.0	47.1	8614	98.3	101.5	154.1	6	7516.0	2522.8
NL10235	44.7	44.5	99.2	184.4	44.5	8551	97.6	115.7	159.0	6	6441.9	2172.6
NL10301	52.8	53.9	95.8	180.7	53.9	8654	98.8	115.6	163.9	8	5260.1	2205.5
NL10318	49.5	50.2	97.0	148.6	50.2	8634	98.6	100.6	135.8	6	5202.4	2177.2
NL10437	47.9	49.1	95.1	184.0	49.1	8555	97.7	108.4	157.3	6	5237.6	1987.5
NL10444	56.4	59.7	102.5	178.2	59.7	8582	98.0	112.5	150.2	10	8328.3	3617.8
NL10538	55.1	56.9	95.0	143.6	56.9	8512	97.2	118.8	129.7	3	5273.4	2374.8
NL10617	50.8	51.2	98.2	165.2	51.2	8599	98.2	109.1	146.7	5	6735.3	2363.9
NL10633	49.2	49.7	99.5	171.8	49.7	8606	98.2	107.3	149.3	8	6695.2	2418.2
NL10644	47.6	47.8	101.3	178.4	47.8	8570	97.8	112.9	155.1	7	7579.2	2451.5
NL10722	43.7	42.4	101.2	165.3	42.4	8642	98.7	107.6	142.8	7	6754.2	2143.2
NL10738	48.8	49.4	105.3	181.9	49.4	8639	98.6	118.5	157.6	9	9147.8	2968.5
NL10807	47.7	47.4	101.4	165.6	47.4	8632	98.5	114.2	148.8	8	7863.0	2422.3
NL10818	51.5	51.4	96.8	160.7	51.4	8616	98.4	120.6	144.6	9	6686.1	2319.3
NL10918	54.6	55.5	93.8	159.6	55.5	8533	97.4	113.5	137.0	6	5698.0	2296.0
NL10929	50.3	49.7	100.5	174.2	49.7	8517	97.2	115.1	162.3	9	7639.4	2622.4
NL10934	56.8	57.8	97.7	154.8	57.8	8421	96.1	120.7	144.4	3	6545.8	2902.4
Urban Background
NL01485	43.8	44.5	90.8	181.2	44.5	8710	99.4	114.3	157.4	5	3880.0	1468.5
NL01494	41.2	42.0	88.9	154.2	42.0	8745	99.8	106.5	142.9	3	3201.3	1281.6
NL01495	44.2	43.8	92.5	153.8	43.8	8748	99.9	101.8	133.5	5	3879.7	1719.3
NL10133⁴	45.1	45.4	102.3	158.7	45.4	8519	97.2	94.5	144.9	3	7044.2	2290.4
NL10138	49.4	50.6	107.5	158.4	50.6	8623	98.4	107.0	153.2	6	9126.5	3036.4
NL10241	46.6	46.9	103.0	177.6	46.9	8632	98.5	118.3	162.2	7	6923.0	2504.0
NL10247⁴	48.6	48.8	108.3	170.0	48.8	8604	98.2	105.5	146.2	10	9033.2	3111.8
NL10404	52.6	55.6	97.9	160.0	55.6	8586	98.0	107.5	145.8	9	5499.6	2812.3
NL10418	46.1	47.2	97.4	173.6	47.2	8644	98.7	122.2	161.5	6	5447.4	2156.3
NL10442	49.6	50.8	103.3	174.8	50.8	8636	98.6	119.1	162.1	7	7419.5	2768.7
NL10446	47.5	49.9	95.1	159.1	49.9	8618	98.4	112.9	146.5	5	4948.9	2009.5
NL10643	46.4	47.1	99.8	164.2	47.1	8649	98.7	108.0	145.3	6	6422.3	2182.3
NL10742	47.3	46.9	100.6	178.8	46.9	8617	98.4	114.0	153.6	9	7337.1	2399.9
NL10938⁴	51.9	52.6	94.4	170.7	52.6	8632	98.5	119.2	151.6	5	4997.3	2167.3
NL49003	49.2	50.7	94.0	148.3	50.7	8713	99.5	105.3	131.5	2	4598.5	1925.3
NL49014	49.9	51.4	99.7	156.3	51.4	8634	98.6	109.8	137.1	7	6237.8	2494.8
Roadside
NL01489	38.6	38.4	89.4	163.8	38.4	8743	99.8	102.6	148.4	2	2858.8	1283.5
NL01493	37.9	38.9	81.9	143.4	38.9	8752	99.9	105.8	130.4	2	1438.2	748.0
NL10236	47.1	47.2	101.6	163.0	47.2	8640	98.6	103.6	143.1	9	6960.3	2344.6
NL10449	39.9	40.5	88.3	154.7	40.5	8625	98.5	99.5	140.1	3	3395.3	1127.9
NL10550	47.9	50.2	90.7	150.3	50.2	8469	96.7	98.0	132.4	2	3442.7	1543.7
NL10636	43.9	44.0	96.1	150.5	44.0	8640	98.6	100.1	135.8	3	4761.5	1824.2
NL10639	44.4	45.2	94.5	157.2	45.2	8642	98.7	103.0	138.3	4	4856.6	1794.7
NL10641	42.9	42.6	91.1	144.1	42.6	8624	98.4	98.6	127.9	4	4080.4	1433.5
NL49012	46.1	47.6	90.6	144.6	47.6	8745	99.8	100.4	124.2	2	3507.2	1431.1
Industrial
NL01496	48.0	49.2	91.5	151.1	49.2	8741	99.8	97.3	134.4	2	3316.2	1876.7
Rows where the text is greyed out indicates a data capture < 85%
¹ Number of days where the maximum daily rolling 8-h mean of ozone concentrations exceed 120 µg/m³ - Orange color indicates exceedance of > 18 times per calendar year
² Accumulated amount of Ozone over the Threshold value of 40 ppb (May - July), related to vegetation [µg/m³ h] - Blue color indicates exceedance of 18000 [µg/m³ h]
³ Sum of max. 8 hour moving averages > 35 ppb or 70 [µg/m³ d] (WHO)
⁴ These sites are considered suburban background sites under the ozone directive

Table 10: Key concentration values for ozone in 2021 (in μg/m³)

type	mean	n
Annual O₃ means per station type in 2021
Rural Background	49.79	19
Urban Background	47.45	16
Roadside	43.18	9
Industrial	48.02	1

Table 11: Summary table for ozone in 2021 (in μg/m³)

	2019	2020	2021	average_3y¹
Number of exceedance days for O₃
Rural Background
NL10107	18	22	10	17
NL10131	16	20	9	15
NL10230	20	22	6	16
NL10235	18	21	6	15
NL10301	17	18	8	14
NL10437	13	15	6	11
NL10444	19	19	10	16
NL10538	17	11	3	10
NL10617	15	11	5	10
NL10633	16	13	8	12
NL10644	17	16	7	13
NL10722	23	17	7	16
NL10738	19	12	9	13
NL10807	20	12	8	13
NL10918	15	10	6	10
NL10929	17	11	9	12
NL10318	-	15	6	10
NL10818	-	13	9	11
NL10934	-	7	3	5
Urban Background
NL01485	16	14	5	12
NL01494	16	10	3	10
NL01495	16	12	5	11
NL10133	19	15	3	12
NL10138	22	26	6	18
NL10241	12	20	7	13
NL10247	14	26	10	17
NL10404	13	14	9	12
NL10418	17	16	6	13
NL10442	16	21	7	15
NL10446	17	15	5	12
NL10643	17	13	6	12
NL10742	19	16	9	15
NL10938	16	9	5	10
NL49003	16	7	2	8
NL49014	17	13	7	12
Roadside
NL01489	13	13	2	9
NL01493	12	8	2	7
NL10236	19	17	9	15
NL10550	15	11	2	9
NL10639	15	12	4	10
NL10641	16	8	4	9
NL10449	-	12	3	8
NL10636	-	13	3	8
NL49012	-	6	2	4
Industrial
NL01496	16	15	2	11
* A hyphen is used in case of insufficient valid data to provide an annual mean
¹ Number of days averaged over 3 years where the maximum daily rolling 8-h mean of ozone concentrations exceed 120 µg/m³ - Orange color indicates exceedance of > 18 times per calendar year and red of > 25 times per calendar year

Table 12: Number of days where the maximum daily rolling 8-h mean of ozone concentrations exceed 120 µg/m³ in 2019, 2020 and 2021

2.5 Carbon monoxide

	mean¹	P50	P98	max	median	n	%	max.roll.24	max.roll.8	exc_10000²
Key statistics for CO in 2021
Urban Background
NL49014	336.2	324.4	567.9	1576.6	324.4	8497	97.0	934.5	946.5	0
Roadside
NL49007	397.2	370.9	748.1	1568.6	370.9	8558	97.7	1220.8	1152.2	0
NL49012	343.4	314.8	662.8	1412.3	314.9	8724	99.6	980.0	959.0	0
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the future EU limit value from 01-01-2030 (2024/2881/EC) and red of the current EU limit value (2008/50/EC)
² Number of days where the maximum daily 8 hour mean concentrations exceed 10000 µg/m³ - Red color indicates an exceedance of at least 1 time per calendar year

Table 13: Key concentration values for carbon monoxide in 2021 (in μg/m³)

type	mean	n
Annual CO means per station type in 2021
Urban Background	336.19	1
Roadside	370.26	2

Table 14: Summary table for carbon monoxide in 2021 (in μg/m³)

2.6 Black carbon

There currently is no limit value for black carbon as the evidence base is not yet sufficient enough to provide a basis for legally binding limit values (WHO, 2021).

	mean	P50	P98	max	median	n	%	max.roll.24	max.roll.8
Key statistics for BC in 2021
Rural Background
NL01437	0.6	0.4	2.1	9.1	0.4	8692	99.2	4.2	3.6
NL10131	0.6	0.5	2.3	9.3	0.5	8708	99.4	7.7	7.7
NL10444	0.4	0.3	1.9	16.0	0.3	8612	98.3	12.5	13.1
NL10633	0.5	0.3	1.7	14.6	0.3	8455	96.5	11.7	11.1
NL10644	0.6	0.4	2.5	8.1	0.4	8621	98.4	7.6	7.0
NL10807	0.5	0.4	1.6	10.2	0.4	8751	99.9	9.0	9.4
NL10929	0.4	0.3	1.6	9.2	0.3	8603	98.2	5.9	7.0
Urban Background
NL01488	0.7	0.5	2.6	12.3	0.5	8717	99.5	11.3	8.6
NL01494	0.8	0.6	3.0	12.2	0.6	8745	99.8	12.1	7.7
NL10138	0.7	0.5	2.8	7.3	0.5	8723	99.6	3.2	4.6
NL10247	0.7	0.5	3.3	8.3	0.5	8599	98.2	7.8	7.2
NL10742	0.7	0.5	2.6	11.2	0.5	8589	98.0	10.2	10.1
NL10821	0.6	0.4	2.3	10.8	0.4	8727	99.6	10.8	9.0
NL10938	0.4	0.3	1.4	21.1	0.3	8468	96.7	11.7	8.7
NL49003	0.6	0.4	2.3	13.7	0.4	8742	99.8	11.0	11.7
NL49014	0.6	0.4	2.0	17.2	0.4	8643	98.7	12.1	13.3
NL49701	0.6	0.4	2.4	12.8	0.4	8753	99.9	11.0	11.5
Roadside
NL01487	1.2	0.9	4.1	13.7	0.9	8588	98.0	13.2	9.8
NL01491	0.9	0.7	3.2	13.7	0.7	8382	95.7	12.4	9.4
NL01492	1.0	0.8	3.1	29.2	0.8	8721	99.6	5.3	5.6
NL01493	1.3	1.0	4.5	10.7	1.0	8661	98.9	9.8	8.0
NL10237	1.1	0.9	3.8	11.7	0.9	8747	99.9	8.0	8.7
NL10641	0.8	0.7	2.5	11.3	0.7	8674	99.0	10.2	10.1
NL10741	1.1	0.9	3.3	12.2	0.9	8564	97.8	10.5	10.5
NL49007	1.0	0.8	3.4	15.2	0.8	8658	98.8	10.7	11.4
NL49012	0.8	0.6	2.6	15.2	0.6	8746	99.8	11.1	11.8
NL49017	0.9	0.7	2.7	14.3	0.7	8712	99.5	11.0	11.6
NL49020	1.0	0.8	3.2	15.8	0.8	8754	99.9	12.4	12.6
Industrial
NL01496	0.7	0.5	2.7	8.8	0.5	8720	99.5	4.4	5.8
Rows where the text is greyed out indicates a data capture < 85%

Table 15: Key concentration values for black carbon in 2021 (in μg/m³)

type	mean	n
Annual BC means per station type in 2021
Rural Background	0.52	7
Urban Background	0.64	10
Roadside	1.00	11
Industrial	0.69	1

Table 16: Summary table for black carbon in 2021 (in μg/m³)

2.7 Volatile organic compounds

	mean¹	P50	P98	max	median	n	%
Key statistics for benzene in 2021
Rural Background
NL49703	0.35	0.25	1.15	2.85	0.25	346	94.80
Urban Background
NL01485	0.66	0.61	1.76	2.08	0.61	357	97.81
NL01494	0.94	0.89	2.21	2.88	0.89	361	98.90
NL01495	1.01	0.78	3.16	8.16	0.78	345	94.52
NL10643	0.27	0.22	0.77	1.12	0.22	334	91.51
Roadside
NL49017	0.66	0.58	1.60	3.50	0.58	352	96.44
Industrial
NL01484	0.64	0.45	2.45	7.42	0.45	359	98.36
NL01496	0.40	0.32	1.27	5.13	0.32	358	98.08
NL49704	0.54	0.40	1.72	3.31	0.40	347	95.07
Rows where the text is greyed out indicates a data capture < 85%
¹ Orange color indicates exceedance of the future EU limit value from 01-01-2030 (2024/2881/EC) and red of the current EU limit value (2008/50/EC)

Table 17: Key concentration values for benzene in 2021 (in μg/m³)

type	mean	n
Annual benzene means per station type in 2021
Rural Background	0.35	1
Urban Background	0.72	4
Roadside	0.66	1
Industrial	0.53	3

Table 18: Summary table for benzene in 2021 (in μg/m³)

For toluene there is no legally binding limit value. Other VOCs are also measured by the LML, but are excluded from this report.

	mean	P50	P98	max	median	n	%
Key statistics for toluene in 2021
Rural Background
NL49703	0.90	0.54	4.30	8.39	0.54	346	94.80
Urban Background
NL01485	2.20	1.88	6.50	9.03	1.88	357	97.81
NL01494	3.84	3.40	8.87	13.14	3.40	361	98.90
NL01495	3.73	2.88	12.06	18.95	2.88	345	94.52
NL10643	0.51	0.39	1.88	2.53	0.39	334	91.51
Roadside
NL49017	1.99	1.82	4.90	6.25	1.82	352	96.44
Industrial
NL01484	1.39	0.99	5.18	9.04	0.99	359	98.36
NL01496	0.59	0.44	1.94	8.78	0.44	358	98.08
NL49704	1.23	0.62	6.21	9.39	0.62	345	94.52
Rows where the text is greyed out indicates a data capture < 85%

Table 19: Key concentration values for toluene in 2021 (in μg/m³)

type	mean	n
Annual toluene means per station type in 2021
Rural Background	0.90	1
Urban Background	2.57	4
Roadside	1.99	1
Industrial	1.07	3

Table 20: Summary table for toluene in 2021 (in μg/m³)

2.8 Heavy metals

The measurements of lead, arsenic, cadmium and nickel as shown in the tables below are based on PM_2.5 and PM₁₀ filter sampling.

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for Pb in 2021
Rural Background
NL10627	4.0	2.9	17.0	25.2	2.9	174	47.7	PM₁₀
NL10644	5.3	3.4	12.7	77.8	3.4	86	23.6	PM_2.5
Industrial
NL49557	12.8	8.9	45.0	45.0	8.9	163	44.7	PM₁₀
Rows where the text is greyed out indicates a data capture < 45%
¹ Orange color indicates exceedance of the annual EU limit value

Table 21: Key concentration values for lead in 2021 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for As in 2021
Rural Background
NL10627	0.4	0.3	1.9	2.3	0.3	173	47.4	PM₁₀
NL10644	0.4	0.3	1.3	2.5	0.3	86	23.6	PM_2.5
Industrial
NL49557	0.8	0.4	2.0	2.0	0.4	163	44.7	PM₁₀
Rows where the text is greyed out indicates a data capture < 45%
¹ Orange color indicates exceedance of the annual EU limit value

Table 22: Key concentration values for arsenic in 2021 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for Cd in 2021
Rural Background
NL10627	0.1	0.1	0.4	1.1	0.1	180	49.3	PM₁₀
NL10644	0.1	0.1	0.3	0.6	0.1	80	21.9	PM_2.5
Industrial
NL49557	0.2	0.1	1.4	1.4	0.1	163	44.7	PM₁₀
Rows where the text is greyed out indicates a data capture < 45%
¹ Orange color indicates exceedance of the annual EU limit value

Table 23: Key concentration values for cadmium in 2021 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for Ni in 2021
Rural Background
NL10627	0.7	0.6	1.7	2.9	0.6	179	49.0	PM₁₀
NL10644	0.6	0.5	1.6	2.6	0.5	87	23.8	PM_2.5
Industrial
NL49557	3.0	2.5	13.9	13.9	2.5	163	44.7	PM₁₀
Rows where the text is greyed out indicates a data capture < 45%
¹ Orange color indicates exceedance of the annual EU limit value

Table 24: Key concentration values for nickel in 2021 (in ng/m³)

component	mean	n
Annual heavy metals means per station type in 2021
As	0.53	3
Cd	0.15	3
Ni	1.39	3
Pb	7.34	3

Table 25: Summary table for lead, arsenic, cadmium and nickel in 2021 (in ng/m³)

2.9 Benzo(a)pyrene

Benzo(a)pyrene concentrations based on PM₁₀ filter sampling for 2021 are given in the following table.

	mean¹	P50	P98	max	median	n	%
Key statistics for benzo(a)pyrene in 2021
Rural Background
NL10444	0.03	0.01	0.12	0.21	0.01	178	48.8
Urban Background
NL10418	0.05	0.02	0.25	0.33	0.03	182	49.9
Industrial
NL49557	0.24	0.11	1.69	2.18	0.11	167	45.8
Rows where the text is greyed out indicates a data capture < 30%
¹ Orange color indicates exceedance of the annual EU limit value

Table 26: Key concentration values for benzo(a)pyrene in 2021 (in ng/m³)

3 Discussion

For all annual LML data from 1976 up to the present year, please consult the RIVM Data catalog. The monitoring data over several years including long-term trend charts can be assessed in the section on air quality on the Environmental Data Compendium website (Compendium voor de Leefomgeving). This website also provides information about the health impact of certain pollutants. The burden of disease due to air pollution can be significant, even if concentrations comply with the European limit values. Substantial improvements in public health can be achieved with further reduction of concentrations below the limit values.

4 References

RIVM public data catalog for air quality measurements. Accessed via: https://data.rivm.nl/data/luchtmeetnet/. Export id of file used in this report for 2021: EXP-2025-002 (2025-05-19T15:36:28+01:00)
Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe. Official Journal of the European Union. Accessed via: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32008L0050
Directive 2004/107/EC of the European Parliament and of the Council of 15 December 2004 relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient air. Official Journal of the European Union. Accessed via: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32004L0107
Directive (EU) 2024/2881 of the European Parliament and of the Council of 23 October 2024 on ambient air quality and cleaner air for Europe (recast). Official Journal of the European Union. Accessed via: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=OJ:L_202402881
World Health Organization (2021) WHO global air quality guidelines. Particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. Geneva. Licence: CC BY-NC-SA 3.0 IGO. Accessed via: https://iris.who.int/bitstream/handle/10665/345329/9789240034228-eng.pdf
Environmental Data Compendium (CLO) website. Accessed via: https://www.clo.nl/onderwerpen/luchtkwaliteit

Appendix A - Overview of accreditation information and limit values

The following table lists the accreditation certificate numbers for the LML for the measurements reported here and the limit values in µg/m³ for each pollutant from the three relevant guidelines. Measurements are carried out under EN ISO/IEC 17025:2017 accreditation by RIVM (L224) in collaboration with its regional partners DCMR (L520) and GGD Amsterdam (L426) who are accredited according to the same ISO standard. Analysis of heavy metals is outsourced to an external analytical laboratory that is accredited according to EN ISO/IEC 17025:2017 under L026.

component	accreditation_number^a	averaging_period	EU_limit_value	EU_limit_value_revised	WHO_AQG
NO₂	L520, L224, L426	year	40	20	10
PM₁₀	L520, L224, L426	year	40	20	15
PM₁₀	L520, L224, L426	day	50 max 35×^b	45 max 18×^b	45 max 3-4×^b
PM_2.5	L520, L224, L426	year	25	10	5
PM_2.5	L520, L224, L426	day		25 max 18×^b
O₃	L520, L224, L426	max_8_h	120 max 25×^b	120 max 18×^b,c	100 max 3-4×^b
O₃	L520, L224, L426	peak_season			60
SO₂	L520, L224, L426	day	125 max 3×	50 max 18×	40
SO₂	L520, L224, L426	year		20^b
CO	L426	max_8_h	10000	10000	10000
CO	L426	day		4000 max 18×^b	4000 max 3-4×^b
benzene	L520, L426	year	5	3.4	1.7
Pb	sampling L224/analysis L026	year	0.5	0.5	0.5
As	sampling L224/analysis L026	year	0.006	0.006	0.066
Cd	sampling L224/analysis L026	year	0.005	0.005	0.005
Ni	sampling L224/analysis L026	year	0.02	0.02	0.025
benzo(a)pyrene	L224, L426	year	0.001	0.001	0.12
^a L224 is RIVM, L520 is DCMR, L426 is GGD Amsterdam, L026 is the analytical laboratory of TNO
^b max n× means a maximum number of n exceedance days per calendar year - For WHO this is also denoted as the 99th percentile, which is equivalent to 3-4 exceedance days per year
^c Averaged over 3 years

Table 27: Accreditation information and limit values in μg/m³ from EU Directives 2008/50/EC and 2004/107/EC (EU_limit_value),
EU Directive 2024/2881 (EU_limit_value_revised), and WHO global air quality guidelines from 2021 (WHO_AQG)