1School of Environmental Science and Engineering, Collaborative
Innovation Center of Atmospheric Environment and Equipment Technology,
Nanjing University of Information Science and Technology, Nanjing 210044,
2Yale–NUIST Center on Atmospheric Environment, Nanjing University of
Information Science & Technology, Nanjing 210044, China
3Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological
Administration, Department of Atmospheric Physics, Nanjing University of
Information Science and Technology, Nanjing 210044, China
4Department of Atmospheric and Oceanic Science, University of
Maryland, College Park, MD 20742, USA
Received: 07 Jun 2016 – Discussion started: 01 Aug 2016
Abstract. A proton transfer reaction ion-drift chemical ionization mass spectrometer (PTR-ID-CIMS) equipped with a hydronium (H3+O) ion source was developed and deployed near an industrial zone in the Yangtze River Delta (YRD) region of China in spring 2015 to investigate industry-related emissions of volatile organic compounds (VOCs). Air pollutants including formaldehyde (HCHO), aromatics, and other trace gases (O3 and CO) were simultaneously measured. Humidity effects on the sensitivity of the PTR-ID-CIMS for HCHO detection were investigated and quantified. The performances of the PTR-ID-CIMS were also validated by intercomparing with offline HCHO measurement technique using 2,4-dinitrophenylhydrazone (DNPH) cartridges and the results showed fairly good agreement (slope = 0.81, R2 = 0.80). The PTR-ID-CIMS detection limit of HCHO (10 s, three-duty-cycle averages) was determined to be 0.9–2.4 (RH = 1–81.5 %) parts per billion by volume (ppbv) based on 3 times the standard deviations of the background signals. During the field study, observed HCHO concentrations ranged between 1.8 and 12.8 ppbv with a campaign average of 4.1 ± 1.6 ppbv, which was comparable with previous HCHO observations in other similar locations of China. However, HCHO diurnal profiles showed few features of secondary formation. In addition, time series of both HCHO and aromatic VOCs indicated strong influence from local emissions. Using a multiple linear regression fit model, on average the observed HCHO can be attributed to secondary formation (13.8 %), background level (27.0 %), and industry-related emissions, i.e., combustion sources (43.2 %) and chemical productions (16.0 %). Moreover, within the plumes the industry-related emissions can account for up to 69.2 % of the observed HCHO. This work has provided direct evidence of strong primary emissions of HCHO from industry-related activities. These primary HCHO sources can potentially have a strong impact on local and regional air pollution formation in this area of China. Given the fact that the YRD is the largest economic zone in China and is dense with petrochemical industries, primary industrial HCHO emissions should be strictly monitored and regulated.
Revised: 08 Nov 2016 – Accepted: 28 Nov 2016 – Published: 21 Dec 2016
Ma, Y., Diao, Y., Zhang, B., Wang, W., Ren, X., Yang, D., Wang, M., Shi, X., and Zheng, J.: Detection of formaldehyde emissions from an industrial zone in the Yangtze River Delta region of China using a proton transfer reaction ion-drift chemical ionization mass spectrometer, Atmos. Meas. Tech., 9, 6101-6116, doi:10.5194/amt-9-6101-2016, 2016.