Dataset: percent of population covered by local government mask orders in the US

We present a dataset covering the extent of local mask orders between April and August 2020, in states which did not have statewide orders (and hence 100% coverage). We obtained data from national and regional newspaper and broadcaster web-based articles, and city and county web pages. The information that we abstracted included: city or county of ordinance, date that the ordinance took effect, and the population of the city or county. In 14 states, city or county governments issued mask-wearing orders, and from our dataset it can been seen that the median population covered in the states was 37.5%; the coverage ranged from 1.6% (New Hampshire) to 77.1% (Arizona). The dataset can be accessed from: https://doi.org/10.7939/DVN/A9C1UU

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Introduction
By August 9, 2020, governors in 35 US states had issued statewide mandates for persons to wear COVID-19 protective face masks 1 . These mandates ensured that the entire state populations were covered, although population adherences to the mandates were not complete 1 . In 15 of the remaining 16 states, until September 9, some local governments (county or municipal) had also issued mandates for persons to wear masks. Mask wearing in public has become a bulwark against COVID-19, and it is desirable to determine the population proportions in the states that are only covered by local ordinances. We present a dataset that provides this information.

Methods
Starting with the 14 states with only local mandates (see Figure 1), we searched for lists of counties and towns or cities that introduced mask orders effective September 9 or earlier.
We collected the following data: the state and city or county name; the date each order became effective; the 2019 population of each relevant city or town 2 and county 3 . We used these populations as estimates of the number of people in each area who were under mask orders. If both city or town and county had issued mask orders, we used only the county population as our measure of the number of people covered.

Dataset description
In the accompanying Excel file (Underlying data), in the column 'NAME' we list the counties, cities and towns with mask orders. We identify cities or towns with an "M" (municipality) and counties with a "C." We also show the date that each order came into effect. We embed the internet address of the related newspaper or broadcast article in the "Date in effect" column. We also record the population of each city, county and state. If both a city and its county had a mask order, we used the county population as our indicator of coverage. We recorded the city population in a separate column.
Data on the number of ordinances for cities and counties in each relevant state is shown in Figure 2. Counties took the initiative in Wyoming, Nebraska, Utah, and Tennessee. In states with more orders, including Arizona, South Carolina and Florida, cities took the initiative. In Arizona there was also an order from a Tribal Council. In Figure 1, we show the country map, identifying states with statewide orders (blue), local government only orders (brown), and no orders (light red). In this figure, we also present the percent of each state's population that was covered by mask orders. For the states with statewide orders, coverage is complete (100%). One state, North Dakota, did not have any orders up until our cutoff date of September 9 (in South Dakota, one city, Brookings, enacted an order on September 9). In Figure 3, we show the ranking of states by percent population covered, for states with only local mandates.

Summary
Our dataset shows the population coverage for mask mandates in states where local governments took policy initiatives. Coverage in these states varied widely and is an important component of any analysis of COVID-19 prevention policies.
There is little nationwide information available on the degree of coverage in states with local mandates. There is no central body that collects and organizes this data and makes it publicly available. This dataset addresses that deficiency. However, there are limitations in collecting this information. Firstly, mask order enactment dates keep changing and local governments keep adding or terminating enactments as the local COVID-19 situation changes. Secondly, news bureaus do not always provide the current situation. Finally, data on county and city orders are not always kept in a central place for public information.

Open Peer Review
Reviewer Report 04 January 2021 Yes Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Health Economics, Econometrics, Disease Risk Factor, Health Policy I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
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