Hawaiian volcano inspired vocabulary

Here is a fun video about how Hawaiian volcanoes have affected our vocabulary.

A very bad week for vog

For the past few days the trade winds have failed to clear the air. The air in Kona is in the Orange range, while Waikoloa is not faring much better. On the bright side, this is typical Kona vog, high in PM2.5 but low in SO2. The weak trade winds should continue for a few days more.

The trade winds normally come from a high pressure system to the northeast of Hawaii. But three low pressure systems to the east are pulling the trade winds away from Hawaii. This is a unusual situation and we can hope for better conditions while we are on the Big Island in July.

The wind map below came from Earth Nullschool.

How to predict Vog for the Big Island

During a volcanic eruption, the vog on the Big Island is primarily determined by the direction of the wind. If you can visualize the overall wind patterns for the island, you can see the wind passing over the volcanic emission and where it will go on the island. A tool which allows you to see future wind patterns, will allow you to predict the vog in your area. There is such a tool on the web called Windy.com.

The wind typically blow from the east. When it hits the Big Island eastern point, the wind splits into a northern stream and a southern stream. The southern steam will pass over the volcanic eruptions and typically carry the emission out to sea, while the northern stream stays clean. Both streams may wrap back toward the west coast once they get around the island. The vog at any point along the west coast will be determined by which stream dominates at a certain time and place.

Waikoloa is on the northern part of the west coast will typically get the good air from the northern stream. But changing wind patterns may allow the vog from the southern stream to reach Waikoloa. When there is vog at Waikoloa, it will be just in the Yellow range, even if the vog further south is in the Orange or Red range.

How to find the AQI of Waikoloa

If you googled AQI for Waikoloa, you may get to the Weather Underground for Waikoloa webpage. It will show you an AQI for PM2.5 and claims its source is EPA AirNow. If you go to the AirNow for Hawaii webpage, you will see that there are only five AQI PM2.5 monitoring stations on the Big Island. The closest station to Waikoloa is Kona. You will see that the Weather Underground AQI for Waikoloa is identical to the AirNow AQI for Kona. So when you google the AQI for Waikoloa, you are actually getting the AQI for Kona.

Under normal wind conditions, the emissions from Kilauea are blown south out to sea but wrap around to the southwest coast. The AQI for PM2.5 on the southwest coast is typically worst that the rest of the island, even for places closer to Kilauea. Waikoloa is on the the northwest coast, 27 miles north of Kona, and should have better air quality, but there are no EPA stations above Kona to confirm this.

However, there is a private AQI network, called Purple Air which sells cheap PM2.5 monitors and makes the readings from their customers available on the internet. There are several Purple Air monitors spread across the island, one in Waikoloa and many around Kona. The readings from the Kona monitors show that the Purple Air monitors are consistent among themselves. When the Kona monitors are compared to the Waikoloa monitor, it shows that the air in Waikoloa is much better than in Kona on a day with typical trade winds. But on days that the trade winds fail, the AQI readings in Waikoloa is about the same as in Kona. The reading below was taken on 6/10/18 had typical trade winds.

Note that the Purple Air monitor in near to the AirNow Kona station does not agree with the official AQI reading. Also the Purple Air monitor in Waikoloa sometimes behave erratically.