Air quality monitoring 2016 annual report: Sequoia and Kings Canyon National Parks

Meyer, Erik; Esperanza, Annie

Sequoia and Kings Canyon National Parks (SEKI) periodically experience the worst air quality in the National Park Service. Elevated ground-level ozone (O3) may be the most damaging pollutant in SEKI, when in summer months, concentrations often exceed the federal ozone health standards of greater than 70 parts per billion (ppb) averaged over an 8 hour (h) period. Ozone is a secondary pollutant, formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) combine with warming temperatures and sunlight. Above 70 ppb, ozone may have negative health effects particularly for sensitive groups, such as children, older people, and those with heart or lung disease (Table 1). As O3 increases, others beyond sensitive groups may be affected (EPA 2016). Examples of ozone health effects include chest pain, coughing, throat irritation, congestion, and exasperation of bronchitis, emphysema, and asthma. The harmful effects of increased O3 go beyond human health and into park ecosystems, including widespread damage to sensitive vegetation, which could alter how plants grow, produce and store food. From early June to late October 2016, O3 conditions were monitored and forecasted to employees and the public from two locations in SEKI: the Ash Mountain air quality station located in the foothills and the Lower Kaweah air quality station in the Giant Forest (Thermo TECO 49/49C Inst.; Figure 1). Daily ozone Air Quality Index (AQI) levels were forecasted through an internet-linked automated process that summarizes ozone and meteorology data from each station from the prior day, as well as expected conditions from weather forecasts. The forecasts are then made available through Twitter Inc. (@SequoiaKingsAir) and embedded for greater outreach through the SEKI Air Advisory website (NPS 2015b). At the end of each advisory season, validated data is downloaded from NPS Gaseous Pollutant and Meteorological Data Access Page, and graphics are generated using the OpenAir package in R Statistical Software (Carslaw and Ropkins 2012, R Software 2015). From April to October 2016, the Ash Mountain site measured 87 days exceeding federal health standards (Figure 1). This was the most of any NPS unit, and was followed by the Lower Kaweah station in SEKI (64 days) and the Black Rock station in Joshua Tree N.P. (37 days). Most other NPS O3 stations measured 10 days or less exceeding federal health standards (NPS 2016a). Air quality was poor in SEKI compared to most other NPS sites, and there was a marked increase in exceedance days from recent years. However, this rise can be largely attributed to the more stringent AQI breakpoints recently adopted, as opposed to an increase in O3 concentration. During the SEKI advisory forecast season (June through October) in Ash Mountain, August had the highest number of days at the Unhealthy for Sensitive Groups level or higher (Figure 2, Figure 3), as well as the most hours exceeding health standards (Figure 4). During this period, 718 hours (h) over 80 days exceeded 70 ppb. At Lower Kaweah during the advisory season, August also had the highest number of days at the Unhealthy for Sensitive Groups level or higher (Figure 5, Figure 6), but the most hours exceeding health standards occurred in July (Figure 7). For the monitoring season, 552 h over 59 days exceeded 70 ppb. Particulate matter (PM 2.5) was also monitored for most of the year in Ash Mountain (BAM 1020, E-BAM Inst.). There were no monitoring days that reached Unhealthy AQI levels; 135 days reached Moderate and 158 days were within the Good range. For a more extensive look at air quality conditions in 2016, please refer to figures 8 through 14 at the end of this report.

Air quality monitoring 2016 annual report: Sequoia and Kings Canyon National Parks

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