Air quality measurements in the Netherlands 2018

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 2018 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 2018, 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 2018
Rural Background
NL10107	16.8	14.8	42.2	128.3	14.8	8601	98.2	0	44.5	49.7
NL10131	17.2	14.4	47.6	90.4	14.4	8643	98.7	0	47.7	64.2
NL10133	13.4	11.6	35.4	65.5	11.6	8641	98.6	0	38.8	49.6
NL10230	24.8	17.5	103.5	378.1	17.5	8058	92.0	27	89.9	222.3
NL10235	16.7	14.3	45.2	84.4	14.3	8616	98.4	0	54.8	61.3
NL10246	18.7	15.8	50.1	89.5	15.8	8670	99.0	0	51.9	60.0
NL10301	16.1	13.1	50.1	91.8	13.1	8588	98.0	0	56.8	79.3
NL10318	16.0	12.6	47.4	107.5	12.6	8617	98.4	0	51.8	80.5
NL10437	19.4	16.3	52.1	88.2	16.3	8329	95.1	0	54.4	74.0
NL10444	15.8	12.8	48.9	86.6	12.8	8459	96.6	0	49.3	66.1
NL10538	13.0	8.7	49.0	107.7	8.7	8571	97.8	0	52.2	67.5
NL10617	13.3	10.9	39.5	90.0	10.9	8567	97.8	0	52.0	63.5
NL10633	15.1	12.3	43.8	70.6	12.3	8566	97.8	0	45.3	56.9
NL10644	17.2	14.3	47.5	86.6	14.3	8724	99.6	0	52.2	63.3
NL10722	13.9	11.8	38.1	65.5	11.8	7713	88.0	0	53.6	56.7
NL10738	14.3	11.9	40.2	68.0	11.9	8713	99.5	0	46.5	59.7
NL10807	11.9	9.8	36.2	56.4	9.8	8701	99.3	0	42.4	50.8
NL10818	11.1	8.8	36.2	124.4	8.8	8579	97.9	0	43.2	61.4
NL10918	10.1	7.9	35.1	64.2	7.9	8524	97.3	0	48.4	56.4
NL10929	11.0	9.0	33.1	84.1	9.0	8474	96.7	0	42.0	55.1
NL10934	8.3	6.4	27.7	47.5	6.4	5387	61.5	0	41.9	45.2
NL49703	20.3	16.6	57.5	99.4	16.6	8736	99.7	0	58.8	80.7
Urban Background
NL01485	26.7	23.7	66.3	122.8	23.7	8520	97.3	0	71.6	100.7
NL01488	25.8	21.9	69.0	166.9	21.9	8725	99.6	0	75.8	114.6
NL01494	29.4	26.0	71.4	125.0	26.0	8719	99.5	0	76.8	111.6
NL01495	27.9	24.6	72.4	141.0	24.6	8669	99.0	0	85.4	105.9
NL01912	24.3	21.0	61.1	91.1	21.0	4844	55.3	0	59.0	78.8
NL10138	16.3	13.4	46.4	71.7	13.4	8611	98.3	0	45.3	57.1
NL10241	21.3	17.6	59.8	104.9	17.6	8573	97.9	0	89.1	72.1
NL10247	19.1	16.3	51.8	101.3	16.3	8626	98.5	0	51.7	64.2
NL10404	24.5	19.1	74.2	142.9	19.1	8513	97.2	0	79.2	106.8
NL10418	29.4	25.5	72.6	129.8	25.5	8708	99.4	0	76.2	98.7
NL10442	20.9	17.5	57.4	116.0	17.5	8719	99.5	0	59.8	74.2
NL10446	25.0	20.1	70.7	127.7	20.1	8597	98.1	0	77.4	96.6
NL10549	20.0	18.4	42.8	58.8	18.4	540	6.2	0	50.1	48.3
NL10643	19.9	16.1	56.8	96.8	16.1	8740	99.8	0	54.6	78.3
NL10742	20.8	17.8	54.1	91.2	17.8	8581	98.0	0	58.6	68.2
NL10938	10.5	8.1	35.1	61.5	8.1	8729	99.6	0	43.7	47.8
NL49003	21.5	17.4	61.0	121.1	17.4	8734	99.7	0	60.0	84.1
NL49014	23.1	19.6	59.5	114.8	19.6	8620	98.4	0	62.2	73.6
NL49019	28.1	24.0	72.4	123.7	24.0	8657	98.8	0	72.4	93.5
NL49021	20.0	16.5	55.2	98.9	16.5	8481	96.8	0	57.3	71.8
NL49022	20.9	16.7	61.9	110.4	16.7	8608	98.3	0	61.0	79.4
NL49701	21.5	15.7	67.1	126.1	15.7	8712	99.5	0	65.7	105.4
Roadside
NL01487	35.0	31.6	80.8	119.4	31.6	8706	99.4	0	86.4	101.5
NL01489	32.3	28.1	83.2	133.5	28.1	8722	99.6	0	85.9	107.6
NL01491	32.7	29.0	78.1	131.6	29.0	8617	98.4	0	92.2	123.6
NL01493	38.9	35.5	86.7	151.8	35.5	8713	99.5	0	94.3	116.5
NL01908	30.8	26.9	78.9	126.4	26.9	8735	99.7	0	86.4	99.1
NL10136	26.5	23.8	67.7	105.3	23.8	8474	96.7	0	63.4	77.4
NL10236	22.7	19.7	57.7	95.5	19.7	8666	98.9	0	61.2	76.6
NL10237	27.8	24.7	68.7	108.2	24.7	8584	98.0	0	70.9	90.8
NL10240	30.9	26.7	82.1	175.3	26.7	8588	98.0	0	75.3	124.5
NL10433	35.6	33.4	75.8	110.5	33.4	1715	19.6	0	65.8	85.9
NL10445	31.8	28.1	79.0	134.0	28.1	8618	98.4	0	81.3	110.3
NL10547	17.5	12.6	45.6	51.0	12.6	179	2.0	0	32.7	43.6
NL10550	25.6	22.8	64.2	148.7	22.8	8740	99.8	0	66.7	83.9
NL10636	24.8	20.8	67.5	107.4	20.8	8730	99.7	0	69.6	87.3
NL10639	28.7	24.5	73.6	112.6	24.5	8527	97.3	0	70.3	98.6
NL10641	27.8	25.0	69.7	109.6	25.0	8622	98.4	0	74.5	89.2
NL10741	31.5	28.8	71.6	122.5	28.8	8609	98.3	0	64.1	88.1
NL10937	24.9	22.6	59.1	102.6	22.6	8382	95.7	0	59.9	80.4
NL49002	40.3	36.7	91.5	174.7	36.7	8575	97.9	0	104.2	115.8
NL49007	45.1	42.2	97.7	172.5	42.2	8492	96.9	0	101.6	134.1
NL49012	35.6	31.2	85.5	148.5	31.2	8703	99.3	0	84.9	108.6
NL49017	33.8	30.7	75.8	139.1	30.7	8641	98.6	0	81.9	95.0
NL49020	40.6	37.2	90.1	143.2	37.2	8718	99.5	0	94.1	116.1
Industrial
NL01496	27.0	23.5	77.4	220.6	23.5	8656	98.8	2	93.3	139.7
NL49704	25.5	19.8	73.7	142.9	19.8	8717	99.5	0	80.8	111.9
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 2018 (in μg/m³)

type	mean	n
Annual NO₂ means per station type in 2018
Rural Background	15.62	20
Urban Background	22.65	20
Roadside	31.82	21
Industrial	26.24	2

Table 2: Summary table for nitrogen dioxide in 2018 (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 2018
Rural Background
NL10131	21.3	18.5	63.3	275.8	18.5	8718	99.5	76.6	100.1	6
NL10133	17.3	15.9	54.4	114.5	15.9	8689	99.2	114.5	86.2	4
NL10230	21.3	18.5	60.8	138.8	18.5	8729	99.6	85.2	112.4	6
NL10235	17.0	14.7	50.5	140.1	14.7	8654	98.8	81.0	90.7	4
NL10246	17.9	15.9	53.1	106.8	15.9	8697	99.3	87.7	94.0	4
NL10318	19.3	15.9	63.3	264.3	15.9	8615	98.3	79.4	122.8	8
NL10437	17.9	14.7	56.9	347.5	14.7	8575	97.9	126.9	108.1	5
NL10444	16.5	14.7	51.8	100.4	14.7	8517	97.2	94.0	80.9	4
NL10538	20.4	15.9	71.0	1409.9	15.9	8622	98.4	176.3	474.2	15
NL10617	17.3	15.9	55.6	168.3	15.9	8249	94.2	77.2	86.3	3
NL10633	17.7	14.7	58.2	199.0	14.7	8539	97.5	92.8	106.8	4
NL10644	17.3	14.7	53.1	100.4	14.7	8691	99.2	72.5	82.5	2
NL10722	18.6	15.9	54.4	119.6	15.9	8573	97.9	76.1	100.0	6
NL10738	20.1	17.2	62.0	234.8	17.2	8479	96.8	86.3	104.9	8
NL10807	17.9	15.9	51.8	170.8	15.9	8676	99.0	72.2	91.2	4
NL10818	16.9	14.7	56.9	138.8	14.7	8421	96.1	57.9	96.1	2
NL10918	16.5	13.4	56.9	205.4	13.4	8575	97.9	63.8	82.3	6
NL10929	15.7	13.4	48.0	184.9	13.4	8511	97.2	71.6	97.6	0
NL10934	17.8	14.7	56.9	190.0	14.7	8685	99.1	73.3	118.5	6
NL49703	17.4	14.6	49.6	120.6	14.6	8651	98.8	71.0	81.3	5
Urban Background
NL01485	21.7	19.3	56.5	171.6	19.3	8672	99.0	171.6	89.3	6
NL01488	20.2	16.9	56.3	685.9	16.9	8408	96.0	379.0	303.7	8
NL01494	22.0	19.6	56.5	159.5	19.6	8584	98.0	154.9	80.8	5
NL01495	20.9	18.6	52.2	118.5	18.6	8414	96.0	73.2	81.2	4
NL01912	19.8	18.0	45.2	158.2	18.0	4799	54.8	46.3	74.3	0
NL10138	17.5	15.9	50.5	103.0	15.9	8604	98.2	64.1	85.9	3
NL10241	21.6	18.5	62.0	400.0	18.5	8653	98.8	400.0	106.0	7
NL10247	19.9	17.2	56.9	296.3	17.2	8682	99.1	296.3	120.1	5
NL10404	19.8	17.2	56.9	563.8	17.2	8679	99.1	563.8	123.0	5
NL10418	20.6	18.5	59.5	231.0	18.5	8453	96.5	231.0	99.5	6
NL10442	18.5	15.9	50.5	289.9	15.9	8740	99.8	289.9	94.7	2
NL10446	17.7	15.9	53.1	782.7	15.9	8498	97.0	782.7	152.3	3
NL49014	19.4	17.3	48.7	185.2	17.3	8572	97.9	98.0	80.2	4
NL49016	22.2	19.6	59.2	159.3	19.6	8099	92.5	159.3	85.0	8
NL49701	19.9	17.4	52.9	130.3	17.4	8339	95.2	126.5	81.7	6
Roadside
NL01487	24.1	22.0	56.9	173.5	22.0	8204	93.7	173.5	81.1	5
NL01489	22.1	19.6	57.4	782.0	19.6	8180	93.4	79.5	142.0	8
NL01491	21.9	19.6	54.1	142.7	19.6	8380	95.7	142.7	83.4	4
NL01493	24.3	21.7	60.7	311.9	21.7	8627	98.5	165.3	94.7	9
NL01908	23.7	21.1	59.0	156.9	21.1	8686	99.2	156.9	98.3	6
NL10136	20.4	18.5	60.8	972.1	18.5	8707	99.4	68.9	154.0	10
NL10236	20.2	18.5	56.9	497.2	18.5	8656	98.8	497.2	92.1	4
NL10237	21.6	19.8	58.2	539.5	19.8	8632	98.5	539.5	110.5	6
NL10240	21.5	18.5	60.8	283.5	18.5	8627	98.5	283.5	100.6	7
NL10433	23.9	21.1	71.0	96.6	21.1	1732	19.8	90.2	80.8	3
NL10445	23.5	21.1	62.0	457.6	21.1	8710	99.4	457.6	155.0	7
NL10550	20.3	18.5	56.9	204.1	18.5	8608	98.3	204.1	103.6	5
NL10636	19.8	17.2	55.6	365.4	17.2	8685	99.1	365.4	82.0	5
NL10639	21.8	19.8	63.3	1740.1	19.8	8538	97.5	117.3	317.6	8
NL10641	20.0	17.2	60.8	168.3	17.2	8697	99.3	77.5	111.3	7
NL10741	21.7	19.8	60.8	589.4	19.8	8702	99.3	589.4	114.9	9
NL10937	22.8	19.8	64.6	689.2	19.8	8696	99.3	689.2	165.1	15
NL49007	22.5	20.0	58.4	263.0	20.0	8484	96.8	144.4	88.6	8
NL49012	23.6	20.8	58.7	451.5	20.8	8550	97.6	298.5	168.9	9
NL49017	21.5	19.0	56.0	299.0	19.0	8063	92.0	246.2	90.2	6
NL49020	22.5	20.1	57.1	422.8	20.1	8583	98.0	422.8	94.6	7
Industrial
NL01496	22.7	20.5	56.5	132.1	20.5	8549	97.6	88.3	102.0	7
NL49704	20.2	16.7	60.4	339.5	16.7	8636	98.6	81.4	97.9	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 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 2018 (in μg/m³)

type	mean	n
Annual PM₁₀ means per station type in 2018
Rural Background	18.10	20
Urban Background	20.14	14
Roadside	21.99	20
Industrial	21.44	2

Table 4: Summary table for PM₁₀ in 2018 (in μg/m³)

	mean¹	P50	P98	max	median	n	%	max.roll.24	max.roll.8
Key statistics for PM_2.5 in 2018
Rural Background
NL10131	12.2	9.4	39.8	83.7	9.4	8316	94.9	63.8	73.0
NL10230	12.8	9.8	41.3	109.2	9.8	8657	98.8	75.2	90.0
NL10444	10.3	7.6	39.2	80.7	7.6	8464	96.6	65.8	70.6
NL10538	10.3	7.2	40.7	164.6	7.2	8479	96.8	59.6	65.8
NL10644	10.9	8.4	38.2	94.8	8.4	8304	94.8	63.6	75.2
NL10738	12.5	9.6	40.5	100.6	9.6	8624	98.4	66.3	69.7
NL10934	9.8	6.5	39.8	128.3	6.5	8671	99.0	60.9	100.6
NL49703	12.0	9.0	41.2	92.3	9.0	8585	98.0	67.4	74.8
Urban Background
NL01488	12.7	9.1	46.1	372.4	9.1	8560	97.7	372.4	85.4
NL01494	13.7	10.3	44.5	138.8	10.3	8674	99.0	138.8	74.0
NL01495	14.8	11.4	44.9	117.9	11.4	8484	96.8	71.8	73.7
NL10138	10.0	7.5	38.4	99.6	7.5	8733	99.7	99.6	60.9
NL10241	12.7	9.6	42.7	234.6	9.6	8501	97.0	234.6	89.9
NL10247	12.9	10.3	40.3	180.7	10.3	8689	99.2	180.7	86.5
NL10404	10.2	7.0	39.4	350.0	7.0	8627	98.5	350.0	72.8
NL10418	11.0	8.0	39.0	133.1	8.0	8594	98.1	133.1	66.7
NL10643	11.6	8.8	39.0	182.6	8.8	8655	98.8	182.6	72.5
NL10742	11.9	9.2	38.8	286.1	9.2	8612	98.3	286.1	73.1
NL10821	10.3	7.4	39.9	482.2	7.4	8424	96.2	482.2	97.3
NL10938	10.7	7.4	41.5	213.0	7.4	8623	98.4	213.0	95.6
NL49014	10.8	7.5	40.4	96.5	7.5	8509	97.1	96.0	71.7
NL49016	14.1	10.6	46.0	137.1	10.6	8273	94.4	137.1	79.2
NL49701	12.9	9.6	43.6	109.9	9.6	8601	98.2	109.9	76.9
Roadside
NL01487	16.7	13.0	48.2	160.3	13.0	8633	98.6	160.3	77.7
NL01489	14.6	10.7	49.1	103.6	10.7	8413	96.0	74.1	84.0
NL01491	14.2	11.0	44.3	131.1	11.0	8526	97.3	131.1	70.5
NL10136	11.4	8.7	42.4	117.4	8.7	8652	98.8	55.3	61.8
NL10240	12.5	9.3	43.3	169.9	9.3	8634	98.6	169.9	79.3
NL10433	15.5	10.7	56.5	72.9	10.7	1687	19.3	66.4	67.8
NL10448	12.7	9.7	40.6	143.4	9.7	8681	99.1	143.4	69.4
NL10547	8.1	6.0	17.0	247.7	6.0	179	2.0	247.7	53.7
NL10636	12.3	9.5	40.1	217.0	9.5	8535	97.4	217.0	74.1
NL10641	12.0	8.8	40.5	97.4	8.8	8634	98.6	66.0	72.2
NL10741	12.1	9.4	39.1	336.3	9.4	8583	98.0	336.3	70.8
NL10937	10.4	7.1	40.3	392.5	7.1	8637	98.6	392.5	94.2
NL49007	13.0	9.9	44.7	139.7	9.9	8480	96.8	139.7	74.3
NL49012	15.2	11.7	48.6	275.4	11.7	8027	91.6	275.4	76.2
NL49017	13.7	10.4	43.9	218.9	10.4	8479	96.8	218.9	77.4
Industrial
NL01496	11.9	8.7	43.6	125.5	8.7	8634	98.6	72.2	81.8
NL49704	14.1	10.7	44.5	144.3	10.7	8611	98.3	71.8	81.9
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 2018 (in μg/m³)

type	mean	n
Annual PM_2.5 means per station type in 2018
Rural Background	11.35	8
Urban Background	12.01	15
Roadside	13.14	13
Industrial	13.01	2

Table 6: Summary table for PM_2.5 in 2018 (in μg/m³)

	2016	2017	2018	average_3y
Statistics to determine the AEI for PM_2.5
Urban Background
NL01494	11.9	12.6	13.7	12.7
NL10241	12.0	11.5	12.7	12.0
NL10247	11.3	12.2	12.9	12.1
NL10404	9.9	10.2	10.2	10.1
NL10418	10.6	10.3	11.0	10.6
NL10643	11.8	10.8	11.5	11.4
NL10742	10.8	11.6	12.0	11.5
NL10821	10.8	10.2	10.3	10.4
NL10938	10.6	9.6	10.7	10.3
NL49014	11.3	10.1	10.8	10.7
NL49701	12.0	11.8	12.8	12.2
NL10138	-	10.0	10.0	10.0
* 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 2018 is 11.2 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 2018
Rural Background
NL10133	0.8	0.4	4.6	15.0	0.4	7329	83.7	0	4.4	7.5	0	0.6
NL10318	1.1	0.5	6.4	54.0	0.5	5875	67.1	0	8.7	20.5	0	0.9
NL10444	1.0	0.6	4.7	67.7	0.6	8504	97.1	0	7.1	19.7	0	0.9
NL10644	0.6	0.5	3.9	15.1	0.5	8711	99.4	0	4.0	7.5	0	0.8
NL10722	0.8	0.4	5.0	18.7	0.4	5484	62.6	0	6.5	13.4	0	0.8
NL10934	0.5	0.3	2.3	7.0	0.3	5373	61.3	0	3.1	4.7	0	0.4
Urban Background
NL01485	3.2	1.5	21.4	312.2	1.5	8590	98.1	0	27.5	74.9	0	3.0
NL01495	3.0	2.3	11.5	190.6	2.3	8650	98.7	0	29.6	78.7	0	1.9
NL49016	0.7	0.4	3.7	28.7	0.4	8352	95.3	0	6.4	13.2	0	0.7
Industrial
NL01484	4.8	3.0	22.5	383.0	3.0	8738	99.7	2	72.0	178.1	0	5.0
NL01496	3.1	2.4	10.6	113.1	2.4	8672	99.0	0	15.0	32.9	0	2.8
NL49704	1.1	0.5	5.8	39.3	0.5	8623	98.4	0	7.4	14.8	0	1.2
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 2018 to 31 March 2019) 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 2018 (in μg/m³)

type	mean	n
Annual SO₂ means per station type in 2018
Rural Background	0.83	2
Urban Background	2.27	3
Industrial	2.96	3

Table 9: Summary table for sulphur dioxide in 2018 (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 2016, 2017 and 2018 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 2018 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 2018
Rural Background
NL10107	44.1	41.8	123.6	194.5	41.8	8551	97.6	121.7	185.3	27	16499.8	3812.2
NL10131	48.5	45.8	132.1	205.5	45.8	8623	98.4	131.2	192.8	33	23301.3	4970.3
NL10230	43.1	41.6	116.0	168.6	41.6	8608	98.3	100.7	161.3	13	13706.0	3170.7
NL10235	44.7	43.0	122.5	276.9	43.0	8616	98.4	108.9	208.2	20	15296.4	3707.4
NL10301	51.4	52.5	108.4	210.4	52.5	8597	98.1	123.2	184.4	11	9888.6	3074.4
NL10318	46.1	46.3	108.2	204.2	46.3	8593	98.1	112.4	178.8	10	9372.0	2562.5
NL10437	46.1	46.0	115.2	189.0	46.0	8614	98.3	117.0	174.0	13	11875.5	3060.7
NL10444	51.9	54.4	114.4	226.7	54.4	8457	96.5	126.3	190.4	16	12824.8	3690.1
NL10538	52.8	54.5	111.1	183.2	54.5	8638	98.6	119.4	163.2	12	11321.0	3085.7
NL10617	48.5	47.9	116.7	165.7	47.9	8421	96.1	110.5	151.2	16	14644.9	3028.8
NL10633	45.6	45.0	113.6	191.5	45.0	7799	89.0	112.5	166.8	14	10641.0	3011.5
NL10644	44.7	44.3	109.6	195.2	44.3	8624	98.4	108.8	163.3	12	11162.6	2825.5
NL10722	45.7	42.8	124.3	189.2	42.8	8616	98.4	140.7	176.9	22	16311.3	3942.1
NL10738	44.6	44.2	112.8	168.0	44.3	8580	97.9	111.1	153.9	9	11251.9	2770.2
NL10807	49.4	48.2	123.7	191.6	48.2	8590	98.1	136.2	156.4	22	16759.1	3852.6
NL10818	52.7	51.9	125.6	211.4	51.9	8571	97.8	127.0	186.7	30	17774.2	4149.4
NL10918	53.3	53.5	115.1	177.8	53.5	8559	97.7	117.6	162.5	13	13296.2	3395.5
NL10929	50.5	49.7	125.6	189.8	49.7	8497	97.0	127.1	175.5	27	16860.4	3997.7
NL10934	52.0	52.4	108.7	169.3	52.4	8523	97.3	115.1	146.9	6	9858.2	2932.7
Urban Background
NL01485	41.3	41.1	102.2	186.7	41.1	8636	98.6	108.9	156.5	6	6628.3	1887.5
NL01494	39.1	39.2	99.4	158.4	39.2	8665	98.9	94.4	139.8	6	5422.5	1819.3
NL01495	40.0	37.7	108.2	195.1	37.7	8668	99.0	113.3	170.1	13	9114.7	2498.4
NL10133⁴	54.3	53.4	138.0	201.5	53.4	5681	64.9	122.5	187.2	32	19190.9	6348.1
NL10138	51.2	50.6	136.5	206.6	50.6	8613	98.3	128.2	192.6	40	22484.2	5385.9
NL10241	48.4	46.3	132.1	193.7	46.3	8577	97.9	129.0	176.8	37	20718.5	4850.9
NL10247⁴	46.3	43.2	130.2	207.5	43.2	8568	97.8	117.5	193.2	43	20646.7	4767.2
NL10404	44.6	46.5	101.0	167.4	46.5	8652	98.8	107.4	148.9	7	6486.3	1973.9
NL10418	42.3	42.4	108.1	165.4	42.4	8552	97.6	109.6	149.7	15	9218.6	2606.8
NL10442	44.8	44.2	116.2	184.4	44.2	8567	97.8	115.9	160.2	18	12552.9	3260.5
NL10446	45.8	46.8	114.1	186.0	46.8	8649	98.7	121.6	173.7	16	11387.2	3012.7
NL10643	46.4	45.5	118.3	192.8	45.5	8650	98.7	123.6	171.3	17	14153.2	3433.4
NL10742	47.1	45.2	124.0	198.6	45.2	8517	97.2	132.4	176.7	23	16358.4	3810.3
NL10938⁴	51.5	52.0	113.6	181.9	52.0	8573	97.9	123.9	164.2	14	11279.8	3037.4
NL49003	48.9	49.6	114.4	187.0	49.6	8574	97.9	119.5	173.0	15	12033.7	3316.2
NL49014	48.4	48.7	117.1	192.9	48.7	8685	99.1	131.6	169.0	21	13650.3	3344.1
Roadside
NL01489	33.9	31.5	99.9	165.5	31.5	8711	99.4	93.3	141.9	6	6681.2	1877.1
NL01493	36.9	35.7	98.2	149.3	35.7	8747	99.9	102.8	133.0	6	5449.7	1732.2
NL10236	42.5	41.0	112.9	170.0	41.0	8600	98.2	105.4	161.5	12	11200.2	2908.0
NL10433	31.6	32.8	69.2	77.0	32.8	1716	19.6	74.3	73.2	0	0.0	36.2
NL10550	43.8	45.5	100.9	188.6	45.5	8549	97.6	144.9	163.5	7	7293.2	1936.6
NL10636	39.7	39.0	100.5	161.5	39.0	8631	98.5	101.0	141.0	4	6277.5	1851.2
NL10639	43.8	42.3	116.3	186.3	42.3	8486	96.9	114.0	160.0	17	13112.0	3356.5
NL10641	36.7	35.9	96.3	176.8	35.9	8440	96.3	108.9	157.1	4	5494.2	1351.3
NL49012	42.5	42.1	106.8	158.5	42.1	8741	99.8	111.8	144.2	10	9017.6	2423.1
Industrial
NL01496	43.8	44.7	97.1	195.3	44.7	8696	99.3	101.6	156.7	6	6103.7	1893.4
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 2018 (in μg/m³)

type	mean	n
Annual O₃ means per station type in 2018
Rural Background	48.33	18
Urban Background	45.73	15
Roadside	39.98	8
Industrial	43.82	1

Table 11: Summary table for ozone in 2018 (in μg/m³)

	2016	2017	2018	average_3y¹
Number of exceedance days for O₃
Rural Background
NL10107	14	12	27	18
NL10131	17	14	33	21
NL10230	12	10	13	12
NL10235	11	9	20	13
NL10301	7	8	11	9
NL10318	10	6	10	9
NL10437	8	4	13	8
NL10444	10	5	16	10
NL10538	10	3	12	8
NL10617	10	6	16	11
NL10631	3	-	-	3
NL10633	7	3	-	5
NL10644	10	8	12	10
NL10722	16	8	22	15
NL10738	11	11	9	10
NL10807	17	10	22	16
NL10818	7	10	30	16
NL10918	7	1	13	7
NL10929	11	6	27	15
NL10934	3	3	6	4
Urban Background
NL01485	6	2	6	5
NL01494	7	5	6	6
NL01495	3	0	13	5
NL10133	8	9	-	8
NL10138	17	17	40	25
NL10241	9	10	37	19
NL10247	14	12	43	23
NL10404	9	3	7	6
NL10418	9	3	15	9
NL10442	9	7	18	11
NL10446	10	6	16	11
NL10643	12	5	17	11
NL10742	12	13	23	16
NL10938	6	4	14	8
NL49003	6	1	15	7
NL49014	8	6	21	12
Roadside
NL01489	4	2	6	4
NL01493	1	0	6	2
NL10236	13	10	12	12
NL10433	8	3	-	6
NL10550	6	0	7	4
NL10639	4	3	17	8
NL10641	6	1	4	4
NL49012	3	0	10	4
NL10636	-	1	4	2
Industrial
NL01496	5	1	6	4
* 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 2016, 2017 and 2018

2.5 Carbon monoxide

	mean¹	P50	P98	max	median	n	%	max.roll.24	max.roll.8	exc_10000²
Key statistics for CO in 2018
Rural Background
NL10644	222.6	206.9	459.7	963.6	206.9	8499	97.0	657.6	764.8	0
Urban Background
NL10742	264.8	239.8	612.5	1527.6	239.8	8694	99.2	718.3	888.5	0
NL49014	301.9	280.3	584.4	2023.8	280.4	8686	99.2	808.0	1264.2	0
Roadside
NL10741	361.7	330.8	788.4	2157.7	330.8	8741	99.8	820.3	1369.0	0
NL49007	355.9	321.6	766.6	1997.1	321.6	8552	97.6	926.0	1491.9	0
NL49012	381.1	347.7	787.8	1632.5	347.7	8715	99.5	1027.7	1183.5	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 2018 (in μg/m³)

type	mean	n
Annual CO means per station type in 2018
Rural Background	222.59	1
Urban Background	283.37	2
Roadside	366.25	3

Table 14: Summary table for carbon monoxide in 2018 (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 2018
Rural Background
NL01437	0.8	0.6	2.8	5.3	0.6	8561	97.7	4.1	4.7
NL10131	0.8	0.6	2.7	6.1	0.6	8692	99.2	4.1	4.5
NL10444	0.6	0.4	2.5	9.3	0.4	8694	99.2	4.6	5.3
NL10633	0.7	0.5	2.5	5.6	0.5	8686	99.2	4.8	5.5
NL10644	0.8	0.6	2.9	8.6	0.6	8722	99.6	4.9	6.0
NL10807	0.6	0.5	2.3	10.3	0.5	8704	99.4	4.0	4.4
NL10929	0.6	0.4	2.4	8.2	0.4	8386	95.7	3.7	4.3
Urban Background
NL01488	0.9	0.7	3.3	11.6	0.7	8750	99.9	8.3	5.6
NL01494	1.1	0.8	4.1	10.0	0.8	8755	99.9	4.8	6.7
NL10138	0.9	0.6	3.7	10.4	0.6	8690	99.2	5.7	8.3
NL10247	1.0	0.7	3.9	15.8	0.7	8739	99.8	4.9	6.9
NL10742	0.9	0.7	3.1	8.7	0.7	8616	98.4	4.7	5.1
NL10821	0.8	0.5	3.1	11.2	0.5	8701	99.3	4.5	5.9
NL10938	0.6	0.4	2.4	20.5	0.4	8748	99.9	4.1	10.3
NL49003	0.8	0.6	3.1	13.4	0.6	8720	99.5	4.7	5.1
NL49014	0.9	0.7	2.8	6.9	0.7	8744	99.8	5.1	5.7
NL49701	0.8	0.6	2.9	8.4	0.6	8754	99.9	5.4	5.8
Roadside
NL01487	1.6	1.3	4.8	11.1	1.3	8702	99.3	5.9	8.5
NL01491	1.2	0.9	3.8	8.7	0.9	8753	99.9	5.9	6.2
NL01492	1.3	1.0	3.9	12.3	1.0	8561	97.7	6.5	7.4
NL01493	1.9	1.5	5.9	13.1	1.5	8612	98.3	7.1	10.6
NL10237	1.4	1.1	4.7	10.3	1.1	8747	99.9	5.3	7.7
NL10641	1.2	1.0	3.4	6.8	1.0	8743	99.8	5.4	6.1
NL10741	1.6	1.3	4.6	12.2	1.3	8740	99.8	5.1	7.7
NL49007	1.7	1.4	5.2	10.0	1.4	8493	97.0	6.0	7.9
NL49012	1.2	0.9	3.6	8.2	0.9	8725	99.6	4.9	5.7
NL49017	1.3	1.2	3.6	11.6	1.2	8738	99.7	5.8	8.0
NL49020	1.5	1.3	4.7	14.5	1.3	8696	99.3	6.3	8.6
Industrial
NL01496	0.9	0.7	3.4	8.5	0.7	8623	98.4	4.6	5.7
Rows where the text is greyed out indicates a data capture < 85%

Table 15: Key concentration values for black carbon in 2018 (in μg/m³)

type	mean	n
Annual BC means per station type in 2018
Rural Background	0.71	7
Urban Background	0.87	10
Roadside	1.44	11
Industrial	0.92	1

Table 16: Summary table for black carbon in 2018 (in μg/m³)

2.7 Volatile organic compounds

	mean¹	P50	P98	max	median	n	%
Key statistics for benzene in 2018
Rural Background
NL49703	0.76	0.59	1.94	3.32	0.60	340	93.15
Urban Background
NL01485	0.80	0.68	2.33	3.34	0.68	362	99.18
NL01494	0.94	0.84	2.24	4.14	0.84	355	97.26
NL01495	0.97	0.87	2.81	4.75	0.87	361	98.90
Roadside
NL49017	0.78	0.76	1.85	2.20	0.76	338	92.60
Industrial
NL01484	1.28	0.94	5.02	7.58	0.94	362	99.18
NL01496	0.63	0.48	2.28	4.39	0.48	361	98.90
NL49704	0.66	0.50	2.13	4.28	0.50	328	89.86
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 2018 (in μg/m³)

type	mean	n
Annual benzene means per station type in 2018
Rural Background	0.76	1
Urban Background	0.91	3
Roadside	0.78	1
Industrial	0.95	2

Table 18: Summary table for benzene in 2018 (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 2018
Rural Background
NL49703	1.23	0.85	4.45	8.72	0.85	340	93.15
Urban Background
NL01485	2.75	2.31	6.99	12.71	2.32	362	99.18
NL01494	3.07	2.78	7.28	10.61	2.78	355	97.26
NL01495	2.41	2.03	6.44	10.11	2.03	363	99.45
Roadside
NL49017	2.27	1.89	5.88	8.76	1.89	338	92.60
Industrial
NL01484	2.68	1.91	13.01	52.64	1.91	362	99.18
NL01496	0.89	0.69	3.24	6.17	0.69	361	98.90
NL49704	2.00	1.10	8.43	40.01	1.10	328	89.86
Rows where the text is greyed out indicates a data capture < 85%

Table 19: Key concentration values for toluene in 2018 (in μg/m³)

type	mean	n
Annual toluene means per station type in 2018
Rural Background	1.23	1
Urban Background	2.74	3
Roadside	2.27	1
Industrial	1.78	2

Table 20: Summary table for toluene in 2018 (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 2018
Rural Background
NL10627	4.5	3.7	16.0	30.1	3.7	182	49.9	PM₁₀
NL10644	4.2	3.4	14.7	18.5	3.4	69	18.9	PM_2.5
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 2018 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for As in 2018
Rural Background
NL10627	0.5	0.4	1.6	2.3	0.4	182	49.9	PM₁₀
NL10644	0.4	0.3	1.2	1.3	0.3	69	18.9	PM_2.5
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 2018 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for Cd in 2018
Rural Background
NL10627	0.1	0.1	0.4	2.1	0.1	182	49.9	PM₁₀
NL10644	0.1	0.1	0.4	0.4	0.1	69	18.9	PM_2.5
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 2018 (in ng/m³)

	mean¹	P50	P98	max	median	n	%	filter_type
Key statistics for Ni in 2018
Rural Background
NL10627	0.9	0.8	2.0	3.1	0.8	181	49.6	PM₁₀
NL10644	0.6	0.5	1.4	1.4	0.5	69	18.9	PM_2.5
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 2018 (in ng/m³)

component	mean	n
Annual heavy metals means per station type in 2018
As	0.42	2
Cd	0.12	2
Ni	0.73	2
Pb	4.35	2

Table 25: Summary table for lead, arsenic, cadmium and nickel in 2018 (in ng/m³)

2.9 Benzo(a)pyrene

Benzo(a)pyrene concentrations based on PM₁₀ filter sampling for 2018 are given in the following table.

	mean¹	P50	P98	max	median	n	%
Key statistics for benzo(a)pyrene in 2018
Rural Background
NL10444	0.08	0.02	0.48	0.61	0.02	180	49.3
Urban Background
NL10418	0.10	0.04	0.66	0.77	0.04	174	47.7
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 2018 (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 2018: EXP-2025-002 (2025-05-19T15:33:25+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	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)