SUBMICRON AEROSOL PARTICLES IN A SMALL SETTLEMENT NEAR HIGHWAY

J. HOVORKA, Z. STAŇKOVÁ

hovorka@cesnet.cz, zuzka.stankova@gmail.com

Institute for Environmental Studies, Faculty of Science, Charles University in Prague, Benátská 2, 128 01, Prague 2, Czech Republic

Sampling site: small village Koberovice, Czech republic, 49° 35´N, 15° 15´E, altitude 470 m

150 permanent residents; there are solely brown coal and wood used for household heating in the village

sampling station was located on highway-facing edge of the village about 350 meters from D1 highway

sampling heads were positioned 3.5 m above the field

Meeting the EU air quality standards for particulate matter (PM2.5 and PM10) and troposheric ozone is the most difficult task for

the air quality administration of the Czech Republic. Air masses in cities are usually well-mixed, contrary to small settlements

where local sources of air pollution often play a major role.

Study objectives: to resolve contribution of local heating and emission from traffic on highway to the mass and size of

fine aerosol particles in the air of a small settlement situated in proximity to highway

Day of combined influence by traffic and local heating

• higher wind speed and wind direction from the highway sector in the early morning and from the village during the rest of day• low levels of PM0.8 masses (<10 gm-3) except episodes of the highest PM0.8 mass (132 gm-3) near 7 PM caused by heating• moderate particle number concentrations, elevated early morning by traffic

Local heating domination day

• low wind speed and wind direction from the village sector • highest daily average of PM0.8 mass (25 gm-3)• highest mass and number concentrations was recorded in the afternoon (16:00 – 21:00) as consequence of local heating habits• low particle number concentrations excepting peak in early morning at 9 AM associated with morning peak of traffic density

Conclusions

Both mass and number concentrations were not alarmingly high within our winter campaign.

Emissions from the highway contributed to the mass of submicron particles usually by less than 20%, despite moderate (0-50C) ambient temperatures in winter season 2006. There was one exception of about 4 hours of trafic jam at the highway, when aerosol emissions from traffic prevailed over local heating

Elevated PM0.8 mass concentrations are associated with a calm air conditions and diurnal pattern of submicron aerosol mass concentration follows heating habits in the village.

Emissions from the heating and highway traffic on average contributed equally to the total submicron particle concentrations. Aerosol number concentrations exhibited higher variability than mass concentrations.

Further measurement are in the progress in the winter 2007/2008

Traffic domination day

• higher wind speed and wind direction from the highway sector • traffic jam at the highway 6-11AM caused very high ultrafine particle number concentrations (2*104)• though high particle number concentrations (>5*103), particle daily mass concentrations were moderate (<10 gm-3)• several episodes of aerosol high mass conc. again reflect heating habits in the village

Acknowledgement

The study was partially carried out under the project 90-901086 and institutional support of the Institute for Environmental Studies of FSCU in Prague

field

Basic statistic data of total number and mass (=1.5 gcm-3) concentrations recorded during winter campaign.

Particle number# cm-3

Particle massg m-3

Min/max 7.0 102/2.5 105 2.4/132

Median 3.4 103 16.7

Geomean 3.5 103 14.9

Average 4.1 103 17.1

Aerial view of the Koberovice village, D1 highway, and surrounding fields and woods

• recorded number size distributions were usually bi-modal with two distinct modes in ultrafine (GMD 20-30nm) and accumulation (GMD 100 nm) size ranges

• the first mode can be attributed to the traffic and partially to the heating while the second one can be attributed solely to the local heating which was also confirmed by wind speed/direction data and by observation

• there were usually two distinct maxima of the traffic density; morning maximum near 9 AM and afternoon maximum near 5 PM. • local heating habits are following: there were several examples of morning (5:30-8:00 AM) episodes while regular heating started usually round 4:30-6:00 PM and ceased near midnight or very early morning. This depends on ambient temperature

• the percentile of the highest mass concentrations was recorded in the late afternoons (17:30-20:00) what, also confirmed by wind directions, simply trace heating habits in the village

• the percentile of the highest number concentrations can be apportioned to both local heating and highway, when the traffic counts were higher than 1400 h-1

• traffic volumes in the village was of three magnitude lower than at the highway and intra-village traffic did not contribute significantly to the values recorded

• higher NO2 values are associated with higher values of accumulation particle size number concentrations

• there was a snow cover in Koberovice and surrounding fields within the whole sampling campaign

Data: 5 min integrates of number size distribution, 14.6-736.5 nm (SMPS 3936L25,TSI)

15 min integrates of NO and NO2 (APNA- 360, Horiba)

5 min integrates wind speed/direction (Ultrasonic), temperature, humidity (Comterm), global radiation (Thies)

1 hour integrates of traffic volumes (Road and Motorway Directorate of the Czech Republic)

way and habits of the heating – questionnaire and interview; measurement duration: 24th Nov to the 8th Dec 2007

Results

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350 m

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