Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

Abstract

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis 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 account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the ongoing monoterpene 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 ratios by 0.59 ± 0.21 ppbv, 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<sup>−2</sup> h<sup>−1</sup> compared to an estimated clear weather rate of 116 to 193 g km<sup>−2</sup> h<sup>−1</sup>. Considering 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

Spatiotemporal Controls on Observed Daytime Ozone Deposition Velocity Over Northeastern U.S. Forests During Summer

“…Measurements from the laboratory and field at sites other than Harvard Forest suggest that red and white pines emit small amounts of β ‐caryophyllene (a sesquiterpene), α ‐humulene (a sesquiterpene), and α ‐terpinene (a monoterpene; Bouvier‐Brown et al, ; Calogirou et al, ; Duhl et al, ; Geron et al, ; Goldstein et al, ; Helmig et al, , ), which are BVOCs reactive enough to influence the ozone EC flux (Richters et al, ; Shu & Atkinson, ). Emission of BVOCs can increase during periods of ecosystem stress (Duhl et al, ; Hansen & Seufert, ; Niinemets, ; Ormeño et al, ) and from the mechanical disturbance of rain (Haase et al, ; Helmig et al, ; Holzinger et al, ).…”

Environmental conditions regulate the impact of plants on cloud formation

“…Moreover, more biotic and abiotic stressors than discussed here may affect plants' emissions 8 37 and thus the composition and CCN activity of SOA. For example, mechanical stress due to a passing storm can induce higher monoterpene emissions from pine 38 39 , which should affect CCN activity similar to heat but in a more quick and episodic way. We investigated young boreal tree species.…”

Sources of air pollution in a region of oil and gas exploration downwind of a large city

“…It is assumed that these areas are more densely forested based on on-line satellite images. Concentrations of monoterpenes reached a campaign maximum after the thunderstorm on 6/21, which was nearly twice as large as the next highest concentration (Haase et al, 2011).…”