Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)
- ISSN: 16807316
- DOI: 10.5194/acp-11-11465-2011
Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emit- ted from vegetation, monoterpenes are a product of photo- synthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into ac- count episodic conditions that can drastically change produc- tion and release rates into the atmosphere. Here, the monoter- pene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ra- tios by 0.59±0.21ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10’s of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km−2 h−1 compared to an esti- mated clear weather rate of 116 to 193 g km−2 h−1. Consid- ering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.