Weather Effects on Isoprene Emission Capacity and Applications in Emissions Algorithms

Abstract

Many plants synthesize isoprene. Because it is volatile and reacts rapidly with hydroxyl radicals, it is emitted to the atmosphere and plays a critical role in atmospheric chemistry. Determining effective remediation efforts for ozone pollution requires accurate isoprene-emission inventories. Temperature and light effects on isoprene emission from plants over minutes to a few hours are fairly well known, but effects over a few days (i.e., influenced by weather) are also possible. We measured isoprene emission and photosynthesis under constant temperature and light (known as the basal emission rate, which reflects the capacity for isoprene emission) during eight field trips from 1994 to 1996. Measurements were made at the tops of oak trees at two sites between May and September. On six of the trips, the effect of short-term (minutes to hours) temperature changes was also investigated. The basal emission rate of isoprene was highly correlated with the average temperature of the previous two days. Including the average daily dose of photosynthetically active radiation for the previous two days improved the correlation. Using averages from one, four, or seven days before the measurement resulted in lower correlation coefficients. Including a variable basal emission rate will improve the accuracy of isoprene-emission models.

Strong correlation between isoprene emission and gross photosynthetic capacity during leaf phenology of the tropical tree species Hymenaea courbaril with fundamental changes in volatile organic compounds emission composition during early leaf development

“…This is in general agreement with our observations, as highest isoprene emission rates were observed when the photosynthetic capacity reached its maximum in mature leaves investigated in the dry season (Table 1). Assessing the whole range of developmental stages investigated in different seasons, the isoprene emission rate did not show a consistent trend with respect to carbon assimilation on the basis of daily integrated NPP, which is in agreement with earlier results reported by Sharkey et al (1999) and Niinemets et al (2002a). Taking daily integrated values of carbon assimilation (NPP) as a basis, the carbon balance changed considerably with leaf age and even negative values (an overall net loss of carbon by isoprene emission) were found for young and for senescent leaves, respectively.…”

History effect of light and temperature on monoterpenoid emissions from Fagus sylvatica L.

“…Moreover, they appear also to depend on light and temperature levels experienced by the plant in the previous hours, days or even weeks. The dependence on temperature during previous days or weeks has been observed in the case of isoprene (Monson et al, 1994;Sharkey et al, 1999;Pétron et al, 2001;Rapparini et al, 2004) and 2-methyl-3-buten-2-ol (MBO) (Gray et al, 2003(Gray et al, , 2006. This dependence is apparently due to changes in the concentration of enzymes responsible for the production of these compounds (Schnitzler et al, 1997) and is consistent with their hypothesized role as thermal protectant (Sharkey et al, 2008).…”

Volatile organic compounds from vegetation in southern Yunnan Province, China: Emission rates and some potential regional implications

“…This is consistent with other studies in the tropics . It is possible that isoprene emissions increase during the dry season due to higher cumulative radiation exposure as observed by Sharkey et al (1999), Geron et al (2000), and Pe´tron et al (2001), although the cooler nighttime temperatures observed during the dry season at this site (Baker et al, 2005) have been found to reduce isoprene emission potential in these same studies.…”