Volcano Watch — Hawaii State Department of Health updates Ambient Air Quality Data website

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To better inform residents and visitors about current air quality conditions, the State of Hawaii Department of Health (DOH) Clean Air Branch has updated the Hawaii Ambient Air Quality Data website (http://health.hawaii.gov/cab/hawaii-ambient-air-quality-data/), which is best viewed using the Google Chrome browser.

The goal of the updated website is to provide near real-time statewide air quality data online. The website has proven useful to island residents and visitors, as well as state and county officials, all of whom now have a one-stop online resource for DOH air quality information. This resource will be especially useful during future eruptions.

Data for the website is pulled from 17 air quality monitoring stations throughout the state, 10 of which are on the Island of Hawai‘i. This includes six new long-term stations located at Hōnaunau, Kailua-Kona, Kea‘au, Nā‘ālehu, Waikoloa, and a soon-to-be reestablished Pāhoa station. Implementation of this expanded monitoring system was a collaborative initiative between the DOH Clean Air Branch and State Laboratories Division.

Different air pollutants are measured at each of the 17 locations. All Hawai‘i air monitoring stations measure small particulate matter (PM2.5), and most stations measure sulfur dioxide (SO₂).

PM2.5 and SO₂ emissions increase during eruptions and are the key contributors to vog (volcanic air pollution). Other measured pollutants include chemicals frequently found in anthropogenic (human-caused) air pollution, including large particulate matter (PM10), carbon monoxide (CO), ozone (O3), and nitrogen dioxide (NO2). Website users can sort data by pollutant or location.

The opening page of the website displays Air Quality Index (AQI) values for each air monitoring station. The AQI is a national standard that indicates how clean or polluted the air is using a six-tiered color-coded system: good (green), moderate (yellow), unhealthy for sensitive groups (orange), unhealthy (red), very unhealthy (purple), or hazardous (maroon). It also provides information on associated health effects and who may be affected at each level.

The AQI is a calculated number based on the concentration of the pollutant in the air. The higher the AQI value, the greater the air pollution level and the greater the health concern.

Values shown on the website are for the pollutant with the highest AQI for the respective site. To view current and previous AQIs in a graphical format, click on a specific station. To display AQI values for a specific pollutant, select from pollutants listed below the "Air Quality Index" tab.

Average hourly concentrations for each monitored pollutant (PM10, PM2.5, SO₂, CO, O3, and NO2) can be viewed by selecting "Pollutant" in the "Air Quality Index" dropdown menu. Select the pollutant of interest to display hourly concentrations in parts per million (ppm) or micrograms per cubic meter (µg/m3). This data is available in both map and table formats. To access the table format, click on "Hourly Monitoring Data" under the "Reports" tab.

Hawai‘i Short Term SO₂ Advisory data can be viewed by selecting "SO₂ Advisory" from the "Current Air Quality" tab. Unlike the main webpage, which provides average hourly concentrations, the "SO₂ Advisory" page provides 15-minute SO₂ average concentrations in ppm and displays corresponding color-coded advisory levels based on specific DOH guidance for short-term SO₂ exposure. The DOH guidance uses the same six-tiered color-coded structure and contains recommended actions for different groups according to SO₂ concentration levels—summarized in the attached table.

The website's "Health" tab provides information related to health effects from air pollution and vog, as well as information about the AQI. Another useful tool on the website is the ability to generate reports of historical air quality data for a chosen time period filtered by station or pollutant.

Hawaii residents and visitors are encouraged to visit the DOH Hawaii Ambient Air Quality Data website to keep informed about changing air quality conditions and to use posted links to available resources to learn more about air pollution and its impacts on health. Additional resources related to air quality and volcanic emissions include the Hawaii Interagency Vog Information Dashboard (https://vog.ivhhn.org) and the USGS Hawaiian Volcano Observatory (https://volcanoes.usgs.gov/vhp/gas.html).

Volcano Activity Update

Kīlauea Volcano is not erupting and its USGS Volcano Alert level remains at NORMAL (https://volcanoes.usgs.gov/vhp/about_alerts.html). Updates for Kīlauea are now issued monthly.

Kīlauea monitoring data have shown no significant changes over the past week. Rates of earthquake activity or seismicity across the volcano remain largely steady with intermittent periods of increased activity each lasting a couple of days. Sulfur dioxide emission rates are low at the summit and below detection limits at Pu‘u ‘Ō‘ō and the lower East Rift Zone. The water pond at the bottom of Halema‘uma‘u continues to slowly expand and deepen.

Mauna Loa is not erupting. Its USGS Volcano Alert level remains at ADVISORY. This alert level does not mean that an eruption is imminent or that progression to an eruption is certain.

During the past week, about 135 small-magnitude earthquakes (nearly all smaller than M2.0) were detected beneath the upper elevations of Mauna Loa. Most of the earthquakes occurred at shallow depths of less than 5 km (about 3 mi) below the surface.

Mauna Loa updates are issued weekly. For more info on the status of the volcano, please go to: https://volcanoes.usgs.gov/volcanoes/mauna_loa/status.html.

One earthquake with three or more felt reports occurred in Hawaii during the past week: a magnitude-2.4 quake 1 km (1 mi) southwest of Volcano at 1 km (1 mi) depth on Nov. 6 at 3:12 p.m. HST.

HVO continues to closely monitor both Kīlauea and Mauna Loa for any signs of increased activity.