Trends in peroxyacetyl nitrate (PAN) in the upper troposphere and lower stratosphere over southern Asia during the summer monsoon season: regional impacts

Fadnavis S., Schultz M. G., Semeniuk K., Mahajan A. S., Pozzoli L., Sonbawne S., ...More

ATMOSPHERIC CHEMISTRY AND PHYSICS, vol.14, no.23, pp.12725-12743, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 23
  • Publication Date: 2014
  • Doi Number: 10.5194/acp-14-12725-2014
  • Journal Name: ATMOSPHERIC CHEMISTRY AND PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.12725-12743
  • Istanbul Technical University Affiliated: Yes

Abstract

We analyze temporal trends of peroxyacetyl nitrate (PAN) retrievals from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) during 2002 2011 in the altitude range 8-23 km over the Asian summer monsoon (ASM) region. The greatest enhancements of PAN mixing ratios in the upper troposphere and lower stratosphere (UTLS) are seen during the summer monsoon season from June to September. During the monsoon season, the mole fractions of PAN show statistically significant (at 2 sigma) positive trends from 0.2 +/- 0.05 to 4.6 +/- 3.1 ppt yr(-1) (except between 12 and 14 km) which is higher than the annual mean trends of 0.1 +/- 0.05 to 2.7 +/- 0.8 ppt yr(-1). These rising concentrations point to increasing NOx (= NO NO2) and volatile organic compound (VOC) emissions from developing nations in Asia, notably India and China